Film formation apparatus and film formation method and cleaning method

ABSTRACT

The purpose of the invention is to provide a film formation apparatus capable of forming an EL layer with a high purity and a high density, and a cleaning method. The invention is a formation of an EL layer with a high density by heating a substrate  10  by a heating means for heating a substrate, decreasing the pressure of a film formation chamber with a pressure decreasing means (a vacuum pump such as a turbo-molecular pump, a dry pump, or a cryopump) connected to the film formation chamber to 5×10 −3  Torr (0.665 Pa) or lower, preferably 1×10 −3  Torr (0.133 Pa) or lower, and carrying out film formation by depositing organic compound materials from deposition sources. In the film formation chamber, cleaning of deposition masks is carried out by plasma.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a film formation apparatus and a filmformation method employed for film formation of a film formable material(hereinafter, referred to as a deposition material) by deposition.Additionally, the invention relates to a cleaning method for removing adeposition material adhering to the inner wall or the like by thedeposition. Particularly, the invention is an efficient technique in thecase an organic material is used as the deposition material.

2. Related Art

In recent years, investigations of light emitting apparatuses comprisingEL elements as self-luminous type elements have been enthusiasticallycarried out and specially, light emitting apparatuses using organicmaterials as EL materials have drawn attention. Such a light emittingapparatus is called as an organic EL display (OELD) or an organic lightemitting diode (OLED).

The EL element comprises a layer (hereinafter referred to as an ELlayer) containing an organic compound capable of emittingelectroluminescence by electric field application, an anode, and acathode. The luminescence in the organic compound includes lightemission (fluorescence) at the time of returning to the normal statefrom the singlet state and light emission (phosphorescence) at the timeof returning to the normal state from triplet state and a light emittingapparatus to be manufactured by the film formation apparatus and thefilm formation method of the invention is applicable for cases usingboth fluorescence and phosphorescence.

The light emitting apparatus has a characteristic that it has no problemin the visible angle because it is self-luminous type, not a liquidcrystal display apparatus. That is, as a display to be employedoutdoors, the apparatus is more suitable than a liquid crystal displayand application in various manners has been proposed.

The EL element has a structure in which the EL layer is sandwichedbetween a pair of electrodes and the EL layer generally has a layeredstructure. A typical example is a layered structure of a holetransporting layer/a light emitting layer/an electron transporting layerproposed by Tang, Eastman Kodak Co. The structure has a remarkably highlight emitting efficiency and almost all of light emitting apparatuseswhich have been presently investigated and developed employ thestructure.

Further, structures of a hole injecting layer/a hole transportinglayer/a light emitting layer/an electron transporting layer formedsuccessively on an anode and of a hole injecting layer/a holetransporting layer/a light emitting layer/an electron transportinglayer/an electron injecting layer may be employed. A fluorescentcoloring material or the like may be doped in the light emitting layers.Further, these layers may be formed by using materials all with lowmolecular weights or using materials all with high molecular weights.

Incidentally, in the specification, all layers to be formed in a cathodeand an anode are generically named as an EL layer. Accordingly, theabove-mentioned hole injecting layer, hole transporting layer, lightemitting layer, electron transporting layer, electron injecting layerare all included in the EL layer.

Also, in the specification, the light emitting element composed of acathode, an EL layer, and an anode is called as an EL element and thereare two types of the EL element: one is a simple matrix type in whichthe EL layer is formed between two kinds of stripe-like electrodesformed at right angles to each other and the other is an active matrixtype in which the EL layer is formed between pixel electrodes connectedto TFT and arranged in a matrix and a counter electrode.

The most important problem of the EL element on practical application isthat the life of the element is insufficient. The deterioration of theelement appears in a way that a non-light emitting region (a dark spot)is widened as the light emission is carried out for a long time and as acause of the deterioration, the EL layer deterioration becomes an issue.

The EL materials forming the EL layer are deteriorated by impuritiessuch as oxygen, water and the like. Further, it may be also possiblethat the deterioration of the EL layer is affected by contamination ofthe EL materials with other impurities.

Further, the EL materials are divided broadly into low molecular weight(monomer-type) materials and high molecular weight (polymer-type)materials and among them, the low molecular weight materials are mainlyformed into films by deposition.

In the case of film formation by a conventional deposition method, adeposition material is used as it is, but the deposition material forthe deposition, is supposed to be contaminated with impurities. That is,oxygen, water, and other impurities, which are one of the causes ofdeterioration of the EL element, are probably mixed therein.

Further, although the purity can be increased by previously refining thedeposition material, there is probability that impurities are mixed bythe time when evaporation is carried out.

EL materials are extremely susceptible to deterioration and easilyoxidized and deteriorated in the presence of oxygen or water. For that,a photolithographic process cannot be carried out after film formationand in order to form a pattern, the film has to be separated using amask having openings (hereinafter referred to as a deposition mask)simultaneously with film formation. Accordingly, almost all of thesublimated organic EL materials adhere to a deposition mask or adeposition-preventing shield (a protective plate for preventing adhesionof the deposition materials to the inner walls of a film formationchamber) in the film formation chamber.

In order to remove the organic EL materials adhering to the depositionmask or the deposition preventing shield, it is required to open thefilm formation chamber to the atmospheric air once, take the depositionmask or the deposition preventing shield outside and then return itagain to the film formation chamber after washing it. However, water oroxygen adsorbed in the deposition mask or the deposition preventingshield exposed to the atmospheric air may be probable to be isolated andtaken in the film at the time of film formation using the organic ELmaterials and thus it is apprehended that adsorbed water or oxygen maybe a factor of promoting deterioration of the organic EL materials.

The invention is achieved in consideration of the above-mentionedproblems and has an aim to provide a film formation apparatus capable offorming an EL layer with a high throughput, a high density, and a highpurity. Another aim of the invention is to provide a film formationmethod using the film formation apparatus of the invention.

Additionally, another aim of the invention is to provide a cleaningmethod for removing deposition materials adhering to jigs installed inthe inside of the film formation apparatus of the invention and theinner wall of the film formation apparatus without exposing them to theatmospheric air and to provide a film formation apparatus provided withthe mechanism for carrying out the cleaning method. Incidentally, in thespecification, the jigs installed in the inside of the foregoing filmformation apparatus include a substrate holder, a mask holder, adeposition preventing shield and a deposition mask.

SUMMARY OF THE INVENTION

A film formation apparatus of the invention is a film formationapparatus for forming a film on a substrate by depositing an organiccompound material from a deposition source installed on the opposite tothe substrate; wherein a film formation chamber to install the substratetherein comprises a deposition source, a means for heating thedeposition source, and a heating means for heating a mask and the filmformation chamber is communicated with a vacuum gas discharge treatmentchamber for vacuum evacuating the film formation chamber.

The invention provides a method for forming a highly dense EL layer byheating a substrate by a means for heating the substrate and furtherdecreasing the pressure to 5×10⁻³ Torr (0.665 Pa) or lower, preferablyto 1×10⁻³ Torr (0.133 Pa) or lower, by a pressure decreasing means (avacuum pump such as a turbo-molecular pump, a dry pump, a cryopump andthe like) connected to the film formation chamber and depositing anorganic compound material from the deposition source to carry out filmformation. Accordingly, in the invention, annealing can be carried outin vacuum simultaneously with the film formation. Alternatively, thesubstrate may be annealed in vacuum before the film formation. Also, thesubstrate may be annealed in vacuum after the film formation. Thetemperature (T₁) of the foregoing substrate is set to be lower than thetemperature (T₃). Further, as the means for heating the substrate, astage (optionally having a function of fixing the substrate) in which aheater and an electric heating wire are formed or a metal mask in whicha heater and an electric heating wire are formed is used to heat whilebeing installed closely to or in the vicinity of the substrate and thetemperature (T₁) of the substrate is controlled to be 50 to 200° C.,preferably 65 to 150° C. In the present invention, by heating thesubstrate, the deposition mask installed closely to or in the vicinityof the heated substrate is also heated. Accordingly, it is preferablefor the deposition mask to be made of a metal material (e.g. a highmelting point metal such as tungsten, tantalum, chromium, nickel,molybdenum and alloys containing these elements) a stainless steel,Inconel, Hastelloy and the like which are hardly deformed by heating(having a low thermal expansion coefficient) and durable to thetemperature (T₁) of the substrate. For example, a low thermal expansionalloy (42 alloy) containing nickel 42% by weight and 58% by weight and alow thermal expansion alloy (36 Invar) containing nickel 36% by weighthaving a thermal expansion coefficient near to that (0.4×10⁻⁶ to8.5×10⁻⁶) of a glass substrate can be exemplified.

Further, it is preferable to install an adhesion prevention means forpreventing the organic compound from adhering to the inner wall of thefilm formation chamber at the time of deposition and the film formationapparatus of the invention is a film formation apparatus for forming afilm on a substrate by depositing an organic compound material from adeposition source installed on the opposite to the substrate; wherein afilm formation chamber to install the substrate therein comprises anadhesion prevention means for preventing film formation in the innerwall, a heating means for heating the adhesion prevention means, thedeposition source, a means for heating the deposition source, and aheating means for heating the substrate or a mask (a deposition mask)and the film formation chamber is communicated with a vacuum gasdischarge treatment chamber for vacuum evacuating the film formationchamber.

As the adhesion prevention means, a deposition preventing shield ispreferable and a heater is installed in the surrounding of thedeposition preventing shield to heat the entire body of the depositionpreventing shield and set the temperature (T₂) of the depositionpreventing shield to be higher than the temperature (T₁) of thesubstrate by at least 10° C., so that an organic compound which is notdeposited on the substrate can be stuck to the substrate. Further, byheating the deposition preventing shield to a certain temperature (thesublimation temperature of the organic compound) or higher, cleaning ofthe film formation chamber can be carried out by evaporating theadhering organic compound.

In the invention, the temperature (T₁) of the substrate at the time offilm formation is set to be lower than the temperature (T₂) of thedeposition preventing shield and the temperature (T₂) of the depositionpreventing shield is set to be lower than the temperature (T₃) of thedeposition source. Further, using the film formation apparatus of theinvention, an inline-type film formation apparatus can be obtained andsuch a film formation apparatus of the invention is a film formationapparatus comprising a load chamber, a transportation chamber, and afilm formation chamber joined to each other in series; wherein the filmformation chamber has a function of conforming the positioning of a maskand a substrate and the film formation chamber is communicated with avacuum gas discharge treatment chamber for vacuum evacuating the filmformation chamber and comprises an adhesion prevention means forpreventing film formation in the inner wall, a heating means for heatingthe adhesion prevention means, the deposition source, a means forheating the deposition source, and a heating means for heating asubstrate or a mask (a deposition mask).

Further, using the film formation apparatus of the invention, amultichamber-type film formation apparatus can be obtained and such afilm formation apparatus of the invention is a film formation apparatuscomprising a load chamber, a transportation chamber, and a filmformation chamber joined to each other in series; wherein thetransportation chamber has a function of conforming the positioning of amask and a substrate and the film formation chamber is communicated witha vacuum gas discharge treatment chamber for vacuum evacuating the filmformation chamber and the film formation chamber comprises an adhesionprevention means for preventing film formation in the inner wall, aheating means for heating the adhesion prevention means, the depositionsource, a means for heating the deposition source, and a heating meansfor heating a substrate or a mask (a deposition mask).

In the above-mentioned respective film formation apparatuses, aplurality of deposition sources are arranged in one film formationchamber and in a single film formation chamber, a plurality offunctional regions can be formed and thus a light emitting elementhaving mixed regions can be formed. Accordingly, in the case an organiccompound film comprising a plurality of functional regions is formedbetween an anode and a cathode of a light emitting element, unlike aconventional layered structure in which clear interfaces exist, astructure in which a mixed region of both of a material composing afirst functional region and a material composing a second functionalregion is formed between the first functional region and the secondfunctional region can be formed. In accordance with the invention,before the film formation or during the film formation, vacuum annealingis carried out, so that molecules in the mixed region can be fittedbetter with one another. Formation of the mixed region moderates theenergy barrier between functional regions. Consequently, the drivingvoltage can be lowered and the deterioration of brightness can beprevented.

The first organic compound and the second organic compound haveproperties selected from a group consisting of a hole injecting propertyto receive hole from an anode, a hole transporting property with higherhole mobility than electron mobility, an electron transporting propertywith higher electron mobility than hole mobility, an electron injectingproperty to receive electron from a cathode, a blocking property toinhibit hole or electron transportation, and a light emitting propertyshowing luminescence and respectively have different properties.

As the organic compound with a high hole injecting property, aphthalocyanine type compound is preferable and as the organic compoundwith a high hole transporting property, an aromatic diamine compound ispreferable and as an organic compound with a high electron transportingproperty, a metal complex containing a quinoline skeleton, a metalcomplex containing a benzoquinoline skeleton, an oxadiazole derivative,a triazole derivative, or a phenanthroline derivative is preferable.Further, as an organic compound showing luminescence, a metal complexcontaining a quinoline skeleton, a metal complex containing abenzoxazole skeleton, or a metal complex containing a benzothiazoleskeleton, which is capable of stably emitting luminescence, ispreferable.

Further preferably, a light emitting region is composed of a hostmaterial and a light emitting material (a dopant) whose excitationenergy is lower than that of the host material and the excitation energyof the dopant is planed to be lower than the excitation energy of a holetransporting region and the excitation energy of the electrontransporting layer. Due to that, dispersion of excited molecules of adopant can be prevented and the dopant can efficiently emitluminescence. Further, in the case a dopant is a carrier trap typematerial, the re-coupling efficiency of the carrier can be heightened.

Further, the invention includes a case that as a dopant, a materialcapable of converting triplet excitation energy to luminescence is addedto the mixed region. In the mixed region formation, the mixed region mayhave a concentration grade.

The film formation apparatus of the invention can be employed for filmformation of not only an organic compound such as the EL material butalso other materials such as metal materials to be employed fordeposition.

Further, by radiating laser beam and scanning the laser beam in theinner wall of the film formation chamber, cleaning can be carried outand thus the film formation apparatus of the invention includes a filmformation apparatus for forming a film on a substrate by depositing anorganic compound material from a deposition source installed on theopposite to the substrate; wherein a film formation chamber to installthe substrate therein comprises a deposition source, a means for heatingthe deposition source, and a heating means for heating a substrate, andthe film formation chamber is communicated with a vacuum gas dischargetreatment chamber for vacuum evacuating the film formation chamber andalso with a cleaning preparatory chamber for radiating laser beam to theinner wall of the treatment chamber.

In the foregoing constitution, the above-mentioned laser beam can bescanned by a galvano-mirror or a polygon mirror to evaporate thedeposited matter adhering to the inner wall of the film formationchamber, a deposition preventing shield, or a deposition mask and carryout cleaning. With the above-mentioned constitution, without the filmformation chamber being exposed to atmospheric air at the time ofmaintenance, cleaning can be carried out.

The above-mentioned laser beam may include laser beam from laser beamsource such as continuously oscillating or pulse oscillating solidlaser, continuously oscillating or pulse oscillating excimer laser, Arlaser, Kr laser and the like. The above-mentioned solid laser includesone or a plurality of types selected from YAG laser, YVO₄ laser, YLFlaser, YAlO₃ laser, glass laser, ruby laser, alexandrite laser,Ti:sapphire laser.

Further, a film formation apparatus having a plasma generation means ina film formation apparatus provided with a deposition source is alsoamong the invention and another constitution regarding the filmformation apparatus of the invention is a film formation apparatus forforming a film on a substrate by depositing an organic compound materialfrom a deposition source installed on the opposite to the substrate;wherein a film formation chamber to install said substrate thereincomprises a deposition source, a means for heating the depositionsource, a heating means for heating a substrate, a mask (a depositionmask), and an electrode on the opposite to the mask and the filmformation chamber is communicated with a vacuum gas discharge treatmentchamber for vacuum evacuating the film formation chamber and plasma isgenerated in the film formation chamber.

In the above-mentioned constitution, the foregoing mask is made of aconductive material and either the foregoing mask or the foregoingelectrode is connected with a high frequency power source (frequency of13 MHz to 40 MHz and high frequency power 20 W to 200 W). The intervalof the mask and the electrode may be adjusted to be 1 cm to 5 cm. Also,in the above-mentioned constitution, the foregoing film formationchamber is provided with a gas introducing means for introducing one ora plurality of kinds of gases selected from Ar, H, F, NF₃, and O intothe film formation chamber and a means for discharging the evaporateddeposition substance.

Further, in the above-mentioned constitution, it is preferable that thedeposition mask to be one electrode for generating plasma is made of amaterial having conductivity and a high melting point metal such astungsten, tantalum, chromium, nickel, molybdenum and alloys containingthese elements) a stainless steel, Inconel, Hastelloy and the like whichare hardly deformed by heating (having a low thermal expansioncoefficient) and durable to plasma is preferable to be employed.Further, in order to cool the heated deposition mask, a mechanism forcirculating a cooling medium (cooling water, cooling gas) in thedeposition mask may be installed.

By the above-mentioned plasma generating means, plasma is generated inthe film formation chamber and the deposited substance adhering to theinner wall of the film formation chamber, the deposition-preventingshield, or the deposition mask is evaporated and discharged out the filmformation chamber to carry out cleaning. With the above-mentionedconstitution, cleaning can be carried out without the film formationchamber being exposed to the atmospheric air at the time of maintenance.

The cleaning method using the film formation apparatus with theabove-mentioned constitution is also included in the invention and acleaning method for removing an organic compound adhering to a filmformation chamber provided with a deposition source and carried out forcleaning the inner wall, an adhesion prevention means for preventingfilm formation on the inner wall, or a mask by generating plasma in thefilm formation chamber.

In the constitution of the above-mentioned cleaning method, theforegoing plasma is generated between the mask and an electrodesinstalled between the mask and the deposition source.

In the constitution of the above-mentioned cleaning method, the plasmais generated by exciting one or a plurality of kinds of gases selectedfrom Ar, H, F, NF₃, and O.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a film formation apparatus of the invention (Embodiment 1).

FIGS. 2A and 2B show charts showing the flows of the invention(Embodiment 1).

FIG. 3 shows a film formation apparatus of the invention (Embodiment 2).

FIGS. 4A and 4B show figures illustrating element structures to beproduced by a film formation apparatus of the invention (Example 1).

FIGS. 5A and 5B show figures illustrating film formation apparatuses ofthe invention (Example 2).

FIG. 6 shows a figure illustrating a film formation apparatus of theinvention (Example 3).

FIG. 7 shows a figure illustrating a film formation apparatus of theinvention (Example 4).

FIG. 8 shows a figure illustrating a light emitting apparatus of theinvention.

FIGS. 9A and 9B show figures illustrating a light emitting apparatus ofthe invention.

FIG. 10 shows a figure illustrating a light emitting apparatus of theinvention.

FIGS. 11A to 11F show figures illustrating one example of an electronicapparatus.

FIGS. 12A to 12C show figures illustrating one example of an electronicapparatus.

FIG. 13 shows a film formation apparatus of the invention (Embodiment3).

FIGS. 14A and 14B show figures showing magnified cross-sectional viewsof deposition masks.

FIG. 15 shows an example of a film formation apparatus (Example 8).

PREFERRED EMBODIMENTS OF THE INVENTION

Embodiments of the invention will be described below.

Embodiment 1

The constitution of a film formation apparatus of the invention will bedescribed with reference to FIG. 1. FIG. 1 is one example of across-sectional view of the film formation apparatus of the invention.

At the time of forming a film by a deposition method, a face down method(referred to as a depositing-up method in some cases) is preferable anda substrate 10 is set in a manner that the face to form a film thereonis face down. The face down method is a method by which a film is formedwhile the face to form film of the substrate being kept face down and insuch a method, adhesion of dust or the like can be suppressed.

As shown in FIG. 1, a heating means, in this case a heater 11, isinstalled adjacently to the substrate 10. By the heating means, thetemperature (T₁) of the substrate can be heated to 50 to 200° C.,preferably 65 to 150° C. Further, a metal mask 12 a fixed in a holder 12b is installed under the substrate 10 and deposition source holders 16 ato 16 c capable of heating at different temperatures respectively arealso installed further under the mask. A deposition source is installedon the opposite to the substrate. In this case, the substrate fixed inthe holder 12 b is exemplified, but it may be fixed by the metal maskusing a permanent magnet.

In FIG. 1, since the metal mask 12 a (referred to as a deposition maskin some cases) is installed adjacently to the substrate 10, when thesubstrate is heated, the metal mask is simultaneously heated. By theheating means for the substrate and the metal mask, the entire body ofthe substrate can be heated. Accordingly, the metal mask (the depositionmask) is preferably made of a metal material which is hardly deformed byheat and durable to the temperature (T₁) of the substrate. Further, thedeposition mask is not limited to a metal material and a mask (of glassor quartz bearing a light shielding film on the surface) made of anothermaterial durable to the temperature (T₁) of the substrate may be used.Incidentally, in this case, the metal mask 12 a installed adjacently tothe substrate 10 is exemplified, the invention is not limited to theexample, and a substrate and a metal mask may be parted from each other.

Further, a heating means (a heater and an electric heating wire) may beinstalled adjacently to the metal mask or a heating means (a heater andan electric heating wire) may be installed in the metal mask itself toheat the metal mask, so that the substrate adjacent to the metal maskcan be heated. By heating the metal mask, the substrate surface in theside where film formation is carried out can be heated.

In this case, the deposition source is composed of deposition sourceholders 16 a to 16 c, organic compounds 17 (17 a to 17 c) forming anorganic compound film, and material chambers 18 (18 a to 18 c)containing organic compounds, and shutters 19 (19 a to 19 c). Further,it is preferable that an organic compound is introduced through anexclusive material exchange chamber (not illustrated) attached to thefilm formation chamber so as to avoid opening of the film formationchamber to the atmospheric air to the utmost. Opening the film formationchamber to the atmospheric air allows water and various gases areadsorbed in the inner wall and released again by vacuum evacuating thechamber. Several tens or hundred hours are taken to subside the releaseof the adsorbed gases and stabilize the vacuum degree to the equilibriumvalue. Therefore, baking treatment for the wall of the film formationchamber is carried out to shorten the time. However, repeat of theopening to the atmospheric air is not an efficient means, an exclusivematerial exchange chamber is preferable to be installed.

In the film formation chamber of the invention, the deposition source orthe substrate in which deposition is to be carried out is better to bemade movable (or rotatable). FIG. 1 shows an example in which thesubstrate to deposit a film thereon is made rotatable and also a metalmask 12 a and a holder 12 b are made rotatable. Alternatively, while thesubstrate being fixed, the deposition holder may be moved in thex-direction or y-direction relative to the substrate to carry outdeposition.

Material chambers 18 (18 a to 18 c) are spaces of the deposition sourceholders 16 a to 16 c made of a conductive metal material and when theorganic compounds 17 (17 a to 17 c) in the insides are heated to therespective sublimation temperature (T₃, T₃′, T₃″) by the heating means[resistance generated at the time of voltage application (resistanceheating)] installed in the deposition source holder, they are evaporatedand deposited on the surface of the substrate 10. The heating means arebasically of a resistance heating type, however a Knudsen cell maybeemployed. Incidentally, in this specification, the surface of thesubstrate 10 includes a thin film formed on the substrate and in thiscase, an anode or a cathode is formed on the substrate.

The shutters 19 (19 a to 19 c) control the deposition of the evaporatedorganic compounds 17 (17 a to 17 c). That is, when the shutters areopened, the organic compounds 17 (17 a to 17 c) evaporated by heatingcan be deposited. Further one or a plurality of other shutters (forexample, shutters for covering the deposition sources until thesublimation from the deposition sources is stabilized) may be installedbetween the substrate 10 and the shutters 19.

Since the film formation time can be shortened, it is preferable thatthe organic compounds 17 (17 a to 17 c) are evaporated by heating beforethe deposition so as to make the deposition possible as soon as theshutters 19 (19 a to 19 c) are opened at the time of the deposition.

Further, in the film formation apparatus of the invention, an organiccompound film having a plurality of functional regions can be formed inone film formation chamber and a plurality of deposition sources areformed according to that. The organic compounds evaporated in therespective deposition sources are deposited on the substrate 10 throughopenings (not illustrated) formed in the metal mask 12 a. Incidentally,the openings of the metal mask may be rectangular, elliptical, or linerand they may be arranged in matrix-like shape or delta arrangement.

Further, impurities (high temperature materials) deposited at a highertemperature than high purity EL materials (middle temperature materials)or impurities (low temperature materials) deposited at a lowertemperature are separated based on the deposition temperature differenceof the deposition materials to carry out film formation only from thehigh purity EL materials. Further, in this specification, substances(impurities) with a higher sublimation temperature than that of the highpurity EL materials are named as high temperature materials andsubstances (impurities) with a lower sublimation temperature are namedas low temperature materials. Also, the high purity EL materialssublimated at a middle temperature between the higher temperature andthe lower temperature are named as middle temperature materials.Incidentally, the materials deposited at respective temperatures arepreviously analyzed by mass spectrometry (GC-MS) to investigate thesublimation temperature of the pure EL materials.

The deposition materials may be subjected to sublimation refining beforedeposition. To refine the deposition materials, a zone refining methodmay be employed.

A deposition-preventing shield 15 for preventing adhesion of an organiccompound to the inner wall at the time of deposition is installed.Installation of the deposition-preventing shield 15 makes it possible todeposit an organic compound which cannot be deposited on the substrate.In the surrounding of the deposition-preventing shield 15, an electricheating wire 14 is adjacently laid and by the electric heating wire 14,the entire body of the deposition-preventing shield 15 can be heated. Atthe time of film formation, the temperature (T₂) of thedeposition-preventing shield 15 is preferable to be higher than thetemperature (T₁) of the substrate by at least 10° C.

Further, the film formation chamber 13 is connected to a vacuumdischarge treatment chamber for vacuum-evacuating the film formationchamber. The vacuum discharge treatment chamber is provided with amagnetically floating type turbo-molecular pump, a cryopump, a dry pump,and the like. Accordingly, 10⁻⁵ to 10⁻⁶ Pa vacuum degree of the filmformation chamber can be achieved and reverse diffusion of impuritiesfrom the pump side and a gas discharge system can be controlled.

Further, the film formation chamber 13 is connected to a gasintroduction system for restoring a normal pressure in the filmformation chamber. In order to prevent introduction of impurities in theinside of the apparatus, as a gas to be introduced, an inert gas such asnitrogen, a rare gas and the like are used. These gases to be introducedinto the inside of the apparatus are subjected to be highly purified bya gas refining apparatus before the introduction into the apparatus.Accordingly, a gas refining apparatus is required to be installed so asto introduce highly purified gases into the apparatus after thepurification. As a result, oxygen and water and other impuritiescontained in the gases can be removed previously, so that introductionof these impurities into the inside of the apparatus can be prevented.

As a material to be employed for the inside of the film formationchamber, aluminum and stainless steel (SUS) specularly polished byelectrolytic polishing can be employed for the inner wall faces sincetheir adsorption capacity of impurities such as oxygen and water can bedecreased by narrowing the surface area. Accordingly, the vacuum degreein the inside of the film formation chamber can be kept at 10⁻⁵ to 10⁻⁶Pa. Also, a material such as a ceramic or the like subjected to thetreatment to extremely decrease the pores may be used for the innermember. These materials are preferable to have a surface smoothnessequivalent to 3 nm or less average roughness between center lines.

In the film formation apparatus of FIG. 1, since the film formation iscarried out using a plurality of material rooms in the same filmformation chamber, a function to move the material rooms containingorganic materials to be employed for the film formation to the optimumpositions under the substrate at the time of film formation or to movethe substrate to the optimum position above the material rooms may beinstalled in order to improve the film formation efficiency.

Using the film formation apparatus shown in FIG. 1 makes it possible tocarry out annealing in vacuum before film formation, annealing in vacuumduring film formation, or annealing in vacuum after film formation toresult in improvement of through-put. Further, an annealing chamberenabled to be vacuum evacuated is connected to the film formationchamber and the substrate is transported in vacuum, so that theannealing in vacuum before film formation in the annealing chamberconnected to the film formation chamber or the annealing in vacuum afterfilm formation can be carried out.

Hereinafter, using the film formation apparatus of FIG. 1, amanufacturing procedure of a light emitting apparatus comprising ananode, an organic compound layer adjacent to the anode, and a cathodeadjacent to the organic compound layer will be described with thereference to FIG. 2. FIG. 2 is a chart showing the flow aftertransportation to the film formation chamber.

At first, a substrate in which an anode is formed is transported to atransportation chamber (not illustrated). As a material for formation ofthe anode, a transparent conductive material is used and an indium-tincompound, zinc oxide and the like can be employed. Next, it istransported to a film formation pretreatment chamber (not illustrated)connected to the transportation chamber (not illustrated). In the filmformation pretreatment chamber, cleaning, oxidation treatment, orheating treatment for the anode surface may be carried out. As thecleaning of the anode surface, the anode surface is cleaned by radiatingUV rays in vacuum. Also, as the oxidation treatment, UV rays areradiated in oxygen-containing atmosphere while heating at 100 to 120° C.being carried out and in the case the anode is an oxide such as ITO, thetreatment is effective. Further, as the heating treatment, heating iscarried out in vacuum at a heating temperature of 50° C. or higher,preferably 65 to 150° C., which the substrate can stand to removeimpurities such as oxygen, water and the like adhering to the substrateand impurities such as oxygen, water and the like existing in the filmformed on the substrate. Especially, since an EL material is susceptiveto deterioration by impurities such as oxygen, water and the like,heating in vacuum before deposition is effective.

Next, the substrate subjected to the above-mentioned pretreatment istransported to a film formation chamber 13 without being exposed toatmospheric air. In the film formation chamber 13, the substrate 10 isset while the face to form a film thereon being set downward.Incidentally, the film formation chamber is preferable to bevacuum-evacuated before the substrate is transported.

The vacuum evacuation means installed while being connected to the filmformation chamber is vacuum-evacuated by an oil-free dry pump from theatmospheric pressure to about 1 Pa and further vacuum-evacuated to thelower pressure by magnetically floating type turbo-molecular pump orcompounded molecular pump. A cryopump may be installed in combination inthe film formation chamber in order to remove water. In such a manner,contamination with organic substances, mainly oil, from the dischargemeans is prevented. The inner wall face is specularly treated byelectrolytic polishing to decrease the surface area and prevent the gasemission. For the purpose of decreasing the gas emission from the innerwall, a heater is preferable to be installed in the outside of the filmformation chamber to carry out baking treatment. Gas emission can besuppressed greatly by the baking treatment. Further, in order to preventthe contamination with the impurities owing to the gas emission, coolingusing a cooling medium at the time of deposition is preferable to becarried out. In such a manner, a vacuum degree as far as 1×10⁻⁶ Pa canbe achieved.

At the time of vacuum evacuation of the film formation chamber, adsorbedwater and adsorbed oxygen adhering to the inner wall of the filmformation chamber, the metal mask, and the deposition preventing shieldcan be also removed simultaneously. Further, the film formation chamberis preferable to be heated before the substrate is transported in. Ittakes time to gradually cool the substrate which is heated by thepretreatment and again heated after being transported in the filmformation chamber to result in decrease of the through-put. Desirably,the substrate which is heated by the heating treatment carried out aspretreatment is transported and set in the film formation chamber as itis heated without being cooled. The apparatus illustrated in FIG. 1,since the heating means for heating the substrate is installed, theheating treatment in the vacuum, which is the pretreatment, can becarried out in the film formation chamber.

Now, heating treatment (annealing) in vacuum in the film formationchamber is carried out before deposition. By the annealing (degassing),impurities such as oxygen, water and the like adhering to the substrateand impurities such as oxygen, water and the like existing in the filmformed on the substrate are removed. In order to remove the impuritiesremoved in such a manner, vacuum evacuation is preferable to be carriedout and the vacuum degree may be increased further.

Next, deposition is carried out in the film formation chamber 13 whichis vacuum-evacuated to the vacuum degree of 5×10⁻³ Torr (0.665 Pa),preferably 10⁻⁴ to 10⁻⁶ Pa. At the time of deposition, a first organiccompound 17 a is evaporated by resistance heating and scattered towardthe substrate 10 when the shutter 19 a is opened at the time ofdeposition. The evaporated organic compound is scattered upward andpassed through the openings (not illustrated) formed in the metal mask12 a and deposited on the substrate 10. Incidentally, at the time ofdeposition, the temperature (T₁) of the substrate is heated to 50 to200° C., preferably 65 to 150° C., by a means for heating the substrate.At the time of deposition, the temperature (T₁) of the substrate is setto be lower than the temperature (T₂) of the deposition preventingshield and the temperature (T₂) of the deposition preventing shield isset to be lower than the temperature (T₃) of the deposition source.Further, the temperature (T₂) of the deposition preventing shield is setto be higher than the temperature (T₁) of the substrate by at least 10°C., so that an organic compound which cannot be deposited on thesubstrate can adhere to the substrate.

In the apparatus illustrated in FIG. 1, a heating means for heating thesubstrate is installed to carry out heating treatment during the filmformation in vacuum. Since the deposition material at the time ofdeposition is probably contaminated with impurities such as oxygen,water and the like, it is effective to carry out heating treatment invacuum during the deposition to emit gases contained in the film. Insuch a manner, while the substrate being heated in vacuum, deposition iscarried out to form a film with a desired film thickness andconsequently, an organic compound layer with a high density and a highpurity can be formed. The organic compound in this case includes organiccompounds having properties such as a hole injecting property to receivehole from an anode, a hole transporting property with higher holemobility than electron mobility, an electron transporting property withhigher electron mobility than hole mobility, an electron injectingproperty to receive electron from a cathode, a blocking property toinhibit hole or electron transportation, and a light emitting propertyshowing luminescence.

In such a manner, deposition of the organic compound 17 a is finishedand a film of the organic compound 17 a is formed on the anode.

Further, in order to decrease the impurities such as oxygen, water andthe like in the obtained organic compound layer, heating under pressureof 1×10⁻⁴ Pa or lower may be carried out to emit water or the likeentrained at the time of deposition. Since the deposition material atthe time of the deposition is probably contaminated with impurities suchas oxygen, water and the like, it is effective to emit gases containedin the film by heating in vacuum after deposition. When annealing afterdeposition is carried out, it is preferable to transport the substrateto another treatment chamber other than the film formation chamberwithout exposing the substrate to the atmospheric air and then carry outannealing in vacuum.

In the apparatus illustrated in FIG. 1, since a heating means forheating the substrate is installed, it is possible to carry out heatingtreatment in vacuum after film formation in the film formation chamber.It is preferable to make the vacuum degree further than that at the timeof deposition and then carry out annealing at 100 to 200° C. afterdeposition. By the annealing (degassing) after film formation, theimpurities such as oxygen, water and the like in the organic compoundlayer formed on the substrate are further removed to form an organiccompound layer with a high density and a high purity.

The steps described so far are for the case of forming a single layer ofthe organic compound 17 a and corresponding to the flow shown in FIG.2A.

Thereafter, the above-mentioned single layer formation steps arerepeated to make desired organic compound layers and finally a cathodeis laminated. Incidentally, in the case of layering different depositionmaterials (organic compounds and a cathode material), layering steps maybe carried out in different film formation chambers or entirely in asingle film formation chamber. As the material for the cathode,materials containing magnesium (Mg), lithium (Li), or calcium (Ca) witha small work function are employed. Preferably, an electrode made ofMgAg (a material containing Mg and Ag mixed in Mg:Ag=10:1) may be used.Besides, ytterbium (Yb), a MgAgAl electrode, an LiAl electrode, andaLiFAl electrode can be exemplified. Consequently, a light emittingapparatus comprising the anode, the organic compound layers adjacent tothe anode, and a cathode adjacent to the organic compound layers can beproduced. Further, annealing before film formation can be carried out inthe film formation chamber and in that case, the through-put isimproved.

An example of formation of a layered structure of three layers in asingle film formation chamber provided with three deposition sourceswill be described with the reference to the flow shown in FIG. 2B andFIG. 1. On completion of the deposition (first deposition) of theorganic compound layer of the organic compound 17 a by closing theshutter 19 a according to the above-mentioned procedure of the singlelayer formation, an organic compound 17 b in the inside is previouslyheated to the sublimation temperature (T₃′) by a heating means installedin a deposition holder and a shutter 19 b is opened to start thedeposition (second deposition) and form an organic compound layer of theorganic compound 17 b on the organic compound layer of the organiccompound 17 a. Successively, in the same manner, on completion of thedeposition (second deposition) of the organic compound layer of theorganic compound 17 b by closing the shutter 19 b, an organic compound17 c in the inside is previously heated to the sublimation temperature(T₃″) by a heating means installed in a deposition holder and a shutter19 c is opened to start the deposition (third deposition) and form anorganic compound layer of the organic compound 17 c on the organiccompound layer of the organic compound 17 b.

At the time of the first deposition, the second deposition, and thethird deposition, the temperature (T₁) of the substrate is set to belower than the temperature (T₂) of the deposition preventing shield andthe temperature (T₂) of the deposition preventing shield is set to belower than the temperatures (T₃, T₃′, T₃″) of the deposition sources.Incidentally, the temperatures of the respective deposition sourcesdiffer depending on the deposition materials to be used, so that thetemperature (T₁) of the substrate and the temperature (T₂) of thedeposition preventing shield may be properly changed depending on therespective temperatures of the deposition sources. Further, the vacuumdegree is also changed properly at the time of the first deposition, thesecond deposition, and the third deposition.

Further, a plurality of shutters of the deposition sources can be openedsimultaneously to carry out co-deposition. The co-deposition means adeposition method in which simultaneous evaporation of differentdeposition sources by heating is carried out and different substancesare mixed in the film formation step.

At the time of the first deposition, the second deposition, and thethird deposition, since evaporation is carried out while the substratebeing heated in vacuum to carry out film formation until a desired filmthickness is obtained, organic compound layers with a high density and ahigh quality can be obtained. Further, without being exposed to theatmospheric air, the deposition is carried out a plurality of timeswhile the substrate being heated in vacuum so that the molecules in theinterlayers of the respective layers are well fitted with one another.

Accordingly, the deposition of a plurality of different organiccompounds is completed and stacked layers composed of the layer of theorganic compound 17 a, the layer of the organic compound 17 b, and thelayer of the organic compound 17 c are formed on the anode.

Next, in the same manner as the formation of the single layer, in orderto decrease the impurities such as oxygen, water and the like in theobtained organic compound layers, heating under pressure of 1×10⁻⁴ Pa orlower may be carried out to emit water or the like entrained at the timeof deposition. In the case annealing after deposition is carried out,the annealing may be carried out in the film formation chamber orannealing may be carried out in vacuum after the substrate istransported to another treatment chamber other than the film formationchamber without exposing the substrate to the atmospheric air.

The steps described so far are for forming layers of the organiccompounds and corresponding to the flow shown in FIG. 2B.

On completion of layering of desired organic compound layers accordingto the above-mentioned steps, finally a cathode is layered. In such amanner, a light emitting apparatus comprising the anode, the organiccompound layers adjacent to the anode, and a cathode adjacent to theorganic compound layers can be produced. In the case where layers areformed in a single film formation chamber as described above,transportation of the substrate can be omitted and further the timetaken to evacuate the film formation chamber, to heat the substrate, andto gradually cool the substrate can be shortened to result in remarkableimprovement of the through-put.

Further, after the above-mentioned formation of the single layer orstacked layers of the organic compounds is carried out once or aplurality of times, it is preferable to carry out cleaning. The cleaningis carried out by re-sublimation and gas discharge. To carry outre-sublimation, the inner wall of the film formation apparatus and thejigs installed in the inside of the film formation apparatus are heatedand the heating method is carried out by any of heater heating, infraredheating, or UV heating and by combining these heating manners. Further,the re-sublimated deposition materials are preferable to be dischargedimmediately by using a vacuum pump. Also, a gas containing ahalogen-group element is injected through a gas introduction system tocarry out re-sublimation and simultaneously discharge the depositionmaterials in the form of fluorides.

Further, in cleaning carried out in the condition that no substrate isarranged, in the film formation apparatus of FIG. 1, the holder and themetal mask are heated by heating the heating means for the substrate toevaporate the organic compounds adhering to them. The organic compoundsadhering to the deposition preventing shield can be evaporated byheating the deposition preventing shield by an electric heating wire 14.If cleaning is carried out, the heating means for the substrate and theheating means for the deposition preventing shield are preferablycapable of controlling the temperature to the evaporation temperaturesof the organic compounds. At the time of cleaning, the evaporatedorganic compounds are recovered by a gas discharge system (a vacuumpump) and the like to make them reusable.

Embodiment 2

Here, a film formation apparatus different from that of the embodiment 1is illustrated in FIG. 3.

As shown in FIG. 3, an example in which a heater furnace 31 and acleaning preparatory chamber 22 are installed while being connected to afilm formation chamber 33 will be described.

The heater furnace 31 for heating a substrate is made capable ofcarrying out annealing treatment by installing a heater in the outside.By the heater furnace 31, the temperature (T₁) of the substrate iscontrolled to be 50 to 200° C., preferably 65 to 150° C. Further, a gateor a shutter shown as a dotted line in FIG. 3 is installed between theheater furnace 31 and the film formation chamber 33. Although it is notillustrated, a vacuum evacuation means may be additionally installed inthe heater furnace 31. In this embodiment, after annealing is carriedout in vacuum by the heater furnace 31 before deposition, the depositionis carried out by opening the gate.

Further, laser 23 and an optical system 24 are installed in the cleaningpreparatory chamber 22 and it is made possible to radiate laser beam 21from the laser to the inside of the film formation chamber 33 by ascanning means 20. A window made of a material (quartz or the like)through which laser beam 21 can be transmitted is formed in a wallpartitioning the cleaning preparatory chamber 22 and the film formationchamber 33. As the scanning means 20, a galvanomirror or a polygonmirror may be used for scanning to evaporate deposited substancesadhering to the inner wall of the film formation chamber and thedeposition preventing shield and carry out cleaning.

In the case of cleaning in condition that no substrate is disposed, inthe film formation apparatus of FIG. 3, the inner wall of the filmformation apparatus and jigs installed in the inside of the filmformation apparatus are heated by laser beam radiation to carry outre-sublimation. The laser beam 21 includes laser beam from laser beamsource such as continuously oscillating or pulse oscillating solidlaser, continuously oscillating or pulse oscillating excimer laser, Arlaser, Kr laser and the like. The above-mentioned solid laser includesone or a plurality of types selected from YAG laser, YVO₄ laser, YLFlaser, YAlO₃ laser, glass laser, ruby laser, alexandrite laser,Ti:sapphire laser. Among them, pulse oscillating excimer laser and Arlaser which are enabled to enlarge the radiation surface area inradiation face by the optical system 24 are preferable.

Further, a metal mask 32 a fixed in a holder adjacently to the portion(the portion shown by the dotted line in FIG. 3) where a substrate isinstalled is provided and a deposition source holder 36 capable ofheating at independent temperature is installed under it. A depositionsource is installed on the opposite to the substrate.

A material chamber 38 is a space of the deposition source holder 36 madeof a conductive metal material and when the organic compound 37 in theinside is heated to the sublimation temperature (T₃) by the heatingmeans [resistance generated at the time of voltage application(resistance heating)] installed in the deposition source holder, it isevaporated and deposited on the surface of the substrate.

The first shutter 39 controls the deposition of the evaporated organiccompound 37. A second shutter 25 is installed between the heater furnace31 and the first shutter 39. The second shutter 25 is a shutter forcovering the deposition source until the sublimation speed from thedeposition source is stabilized.

Further, a deposition preventing shield 35 for preventing adhesion ofthe organic compound to the inner wall of the film formation chamber atthe time of deposition is installed. Also, in the surrounding of thedeposition preventing shield 35, an electric heating wire 34 is providedand by the electric heating wire 34, the entire body of the depositionpreventing shield 35 can be heated. At the time of deposition, thetemperature (T₁) of the substrate is set to be lower than thetemperature (T₂) of the deposition preventing shield and the temperature(T₂) of the deposition preventing shield is set to be lower than thetemperature (T₃) of the deposition source. Further, the temperature (T₂)of the deposition preventing shield is set to be higher the temperature(T₁) of the substrate by at least 10° C., so that an organic compoundwhich cannot be deposited on the substrate can adhere to the substrate.

Further, the film formation chamber 33 is connected to a vacuumdischarge treatment chamber for vacuum evacuating the film formationchamber. The film formation chamber 33 is also connected to a gasintroduction system for restoring a normal pressure in the filmformation chamber.

Further, also in the apparatus of FIG. 3, heating treatment in vacuumduring the film formation can be carried out by the heater furnace 31.Since the deposition material at the time of deposition is probablycontaminated with impurities such as oxygen, water and the like, it iseffective to carry out heating treatment in vacuum during the depositionto emit gases contained in the film. In such a manner, while thesubstrate being heated in vacuum, deposition is carried out to form afilm with a desired film thickness and consequently, an organic compoundlayer with a high density and a high purity can be formed.

By employing the film formation apparatus shown in FIG. 3, it is madepossible to carry out annealing in vacuum before film formation,annealing in vacuum during film formation, and annealing in vacuum afterfilm formation to result in improvement of the throughput.

The above-mentioned cleaning by laser beam may be carried out every filmformation process and also may be carried out after a plurality of filmformation processes are carried out.

This embodiment can be optionally combined with the embodiment 1.

Embodiment 3

The constitution of another film formation apparatus of the inventionwill be described with the reference to FIG. 13. FIG. 13 shows anexample of a cross-sectional view of another film formation apparatus ofthe invention.

As shown in FIG. 13, an example in which plasma 1301 is generatedbetween a deposition mask 1302 a connected to a high frequency powersource 1300 a through a capacitor 1300 b and an electrode 1302 b will bedescribed.

The deposition mask 1302 a fixed in a holder is installed adjacently tothe portion (the portion shown by the dotted line in the figure) where asubstrate is to be installed and a deposition source holder 1306 capableof heating at respective temperature is installed under it. A depositionsource is installed on the opposite to the substrate.

Further, a material chamber 1308 is a space of the deposition sourceholder 1306 made of a conductive metal material and when the organiccompound 1307 in the inside is heated to the sublimation temperature(T₃) by the heating means (such as a resistance heating method)installed in the deposition holder, it is evaporated and deposited onthe surface of the substrate. Incidentally, at the time of deposition,the electrode 1302 b is moved to the position where the deposition isnot disturbed.

A deposition preventing shield 1305 for preventing the organic compoundfrom depositing on the inner wall of the film formation chamber at thetime of deposition is installed. Further, an electric heating wire 1304is laid adjacently to the surrounding of the deposition preventingshield 1305 and the entire body of the deposition preventing shield 1305can be heated by the electric heating wire 1304. At the time of thedeposition, the temperature (T₁) of the substrate is set to be lowerthan the temperature (T₂) of the deposition preventing shield and thetemperature (T₂) of the deposition preventing shield is set to be lowerthan the temperature (T₃) of the deposition source. Further, thetemperature (T₂) of the deposition preventing shield is set to be higherthan the temperature (T₁) of the substrate by at least 10° C., so thatan organic compound which cannot be deposited on the substrate canadhere to the substrate.

FIG. 14A shows a magnified cross-sectional view of the deposition mask1302 a. Since the deposition mask is a metal mask, at the time ofprocessing by etching technique, the cross-section is not vertical buttapered. FIG. 14B shows an example with a different cross-sectionalstructure of the deposition mask. In both cross-sectional structures,the peripheral parts of the openings are sharp. Therefore, plasma can beeasily generated in the peripheral parts of the openings and due tothat, the portions where adhering substances are required to be cleanedout most, that is, the peripheral parts of the openings where the maskprecision is decreased in the case where the adhering substances areadhered to can be cleaned out. As a method for producing the metal maskother than the etching technique, an electroforming technique isavailable and in this case, the cross-sectional shape becomes anoverhung shape having R in the cross-section.

On completion of deposition, the substrate is taken out and thencleaning is carried out to remove deposition materials adhering to jigsinstalled in the inside of the film formation apparatus and to the innerwall of the film formation apparatus without exposing them to theatmospheric air. At the time of the cleaning, the electrode 1302 b ismoved to the position on the opposite to the deposition mask 1302 a.Further, the gas is introduced into the film formation chamber 1303. Thegas to be introduced into the film formation chamber 1303 may be one ora plurality of types of gases selected from Ar, H, F, NF₃, and O. Next,a high frequency electric field is applied to the deposition mask 1302 afrom the high frequency power source 1300 a to excite the gas (Ar, H, F,NF₃, or O) and generate plasma 1301. In such a manner, plasma 1301 isgenerated in the film formation chamber 1303 and the depositedsubstances adhering to the inner wall of the film formation chamber, thedeposition preventing shield 1305, and the deposition mask 1302 a areevaporated and discharged outside of the film formation chamber. By thefilm formation apparatus shown in FIG. 13, cleaning can be carried outat the time of maintenance without opening the film formation chamber tothe atmospheric air.

In this case, although the example in which plasma is generated betweenthe deposition mask 1302 a and the electrode 1302 b installed betweenthe mask and the deposition source holder 1306 is exemplified, theinvention is not limited to that but include any as long as it comprisesa plasma generation means. Further, a high frequency power source may beconnected to the electrode 1302 b and the electrode 1302 b may be formedto be a mesh type electrode or an electrode just like a shower head intowhich a gas can be introduced.

Further, the above-mentioned cleaning by plasma may be carried out everyfilm formation process and also may be carried out after a plurality offilm formation processes are carried out.

This embodiment can be optionally combined with the embodiment 1.

The invention with the above constitution will be described further indetails in accordance with the examples below.

EXAMPLES Example 1

In this example, production of an element in which mobility of a carrieris improved by moderating the energy barrier existing in organiccompound films and simultaneously functions of a plurality of types ofmaterials are provided as well as functions of the layered structure areseparated will be exemplified.

Regarding the moderation of the energy barrier in the layered structure,a technique to insert a carrier injection layer is found remarkablyeffective. That is, in an interface of the layered structure with a highenergy barrier, a material which moderates the energy barrier isinserted, so that the energy barrier can be designed in the form ofsteps. Consequently, the carrier injection capability from an electrodecan be increased and the driving voltage can be surely decreased to acertain extent. However, there is a problem that increase of the numberof the layers contrarily results in increase of the number of theorganic interfaces. That is supposed to be a reason for that anapparatus with a single layer structure has the top data of the drivingvoltage and power efficiency. In other words, if the such a point issolved, while the advantages (a variety of materials can be used incombination and complicated molecular designs are not required) of thelayered structure being made effective, the driving voltage and thepower efficiency which the single structure has can be achieved.

In this example, in the case an organic compound film composed of aplurality of functional regions is formed between an anode and a cathodeof a light emitting element, unlike a conventional layered structurehaving clear interfaces, a structure having a mixed region containingboth of a material forming a first functional region and a materialforming a second functional region between the first functional regionand the second functional region is formed.

By forming such a structure, the energy barrier existing among thefunctional regions is lowered as compared with that in the conventionalstructure and thus it is supposed that the carrier injection capabilityis improved. That is, the energy barrier among the functional regionscan be moderated by forming the mixed region. Accordingly, the drivingvoltage can be lowered and the brightness deterioration can besuppressed.

As described above, in this example, regarding production of a lightemitting element comprising at least a region (a first functionalregion) in which a first organic compound is capable of performing thefunction and a region (a second functional region) in which a secondorganic compound different from the first organic compound forming thefirst functional region is capable of performing the function and alight emitting apparatus comprising the element, by employing a filmformation apparatus shown in FIG. 1, a mixed region containing anorganic compound forming a first functional region and an organiccompound forming a second functional region between the first functionalregion and the second functional region is formed.

In the film formation apparatus shown in FIG. 1, an organic compoundfilm having a plurality of functional regions is to be formed in asingle film formation chamber and corresponding to that, a plurality ofdeposition sources are installed. A substrate in which an anode isformed is transported and set. The substrate is heated by a heatingmeans and the temperature (T₁) of the substrate is adjusted to be 50 to200° C., preferably 65 to 150° C. Further, at the time of filmformation, the temperature (T₁) of the substrate is set to be lower thanthe temperature (T₂) of the deposition preventing shield and thetemperature (T₂) of the deposition preventing shield is set to be lowerthan the temperature (T₃) of the deposition source.

At first, a first organic compound 17 a stored in a first materialchamber 18 a is deposited. Incidentally, the first organic compound 17 ais previously evaporated by resistance heating and scattered toward thesubstrate by opening a shutter 19 a at the time of deposition.Consequently, a first functional region 210 shown in FIG. 4A can beformed.

While the first organic compound 17 a being deposited, a shutter 19 b isopened to deposit a second organic compound 17 b stored in a secondmaterial chamber 18 b. The second organic compound 17 b is alsopreviously evaporated by resistance heating and scattered toward thesubstrate by opening the shutter 19 b. Here, a first mixed region 211composed of the first organic compound 17 a and the second organiccompound 17 b can be formed.

After a while, only the shutter 19 a is closed and the second organiccompound 17 b is deposited. Consequently, a second functional region 212can be formed.

In this example, although a method for forming the mixed region bysimultaneously depositing two types of organic compounds is described,the mixed region may be formed between the first functional region andthe second functional region by depositing the first organic compoundand then depositing the second organic compound under the depositionatmosphere of the first organic compound.

Next, while the second organic compound 17 b being deposited, a shutter19 c is opened to deposit a third organic compound 17 c stored in athird material chamber 18 c. The third organic compound 17 c is alsopreviously evaporated by resistance heating and scattered toward thesubstrate by opening the shutter 19 c. Here, a second mixed region 213composed of the second organic compound 17 b and the third organiccompound 17 c can be formed.

After a while, only the shutter 19 b is closed and the third organiccompound 17 c is deposited. Consequently, a third functional region 214can be formed.

Finally, a cathode is formed to complete the light emitting element bythe film formation apparatus of the invention.

Further, as another organic compound film, as shown in FIG. 4B, afterthe first functional region 220 is formed using the first organiccompound 17 a, the first mixed region 221 composed of the first organiccompound 17 a and the second organic compound 17 b is formed and furtherthe second functional region 222 is formed using the second organiccompound 17 b. Successively, the second mixed region 223 is formedduring the formation of the second functional region 222 bysimultaneously depositing the third organic compound 17 c by temporarilyopening the shutter 19 c.

After awhile, the shutter 19 c is closed and again the second functionalregion 222 is formed. Finally, a cathode is formed to complete the lightemitting element.

Since the film formation apparatus of FIG. 1 capable of forming theabove-mentioned organic compound film can form the organic compound filmhaving a plurality of functional regions in a single film formationchamber, the interfaces of the functional regions are not polluted withimpurities and also mixed regions can be formed in the interfaces of thefunctional regions. In the above-mentioned manner, a light emittingelement having no clear layered structure (that is, no clear organicinterface) and provided with a plurality of functions can be formed.

Further, the film formation apparatus of FIG. 1 is capable of carryingout vacuum annealing before film formation, during film formation, andafter film formation, and by carrying out vacuum annealing during filmformation, the molecules in the mixed regions are well fitted.Accordingly, the driving voltage can be decreased and the brightnessdeterioration can be suppressed further. By annealing (degassing) afterfilm formation, the impurities such as oxygen, water and the like in theorganic compound layer formed on the substrate are further removed andthe organic compound layer with a high density and a high purity can beformed.

This example can be optionally combined with the embodiment 1, theembodiment 2, or the embodiment 3.

Example 2

The constitution of a film formation apparatus of this example will bedescribed in accordance to FIG. 5. FIG. 5A is an upper face view of thefilm formation apparatus and FIG. 5B is a cross-sectional view. Commonsymbols are assigned to common parts. In this example, formation ofthree types of organic compound films (red, green, and blue) in threefilm formation chambers of an in-line type film formation apparatuscomprising these three film formation chambers will be exemplified.Incidentally, a first film formation chamber 305, a second filmformation chamber 308, and a third film formation chamber 310 arecorresponding to the film formation chamber 13 shown in FIG. 1.

In FIG. 5A, numeral 300 denotes a load chamber and after the loadchamber is vacuum evacuated to decrease the pressure, the substrateinstalled in the load chamber is transported to a first transportationchamber 301. In the first transportation chamber 301, metal masks 303previously fixed in holders 302 are aligned in respective holders andthe substrate 304 before the deposition is mounted on the metal mask303, for which alignment is finished. Consequently, the substrate 304and the metal mask 303 are united and transported to first filmformation chamber 305. Further, in this example, a vacuum dischargemeans and a heating means for the substrate are installed in the firsttransportation chamber 301 to carry out vacuum annealing before thedeposition and remove water contained in the substrate. Further, thereversing mechanism for the substrate may be installed in the firsttransportation chamber 301.

The holder 302 comprises a mask holder, a shaft, a substrate holder, acontrol mechanism, auxiliary pins and the like. The metal mask 303 isfixed while being matched with the projections on the mask holder andthe substrate 304 is mounted on the metal mask 303. The substrate 304 onthe metal mask 303 is fixed by the auxiliary pins.

On completion of the alignment of the metal mask 303, the shaft is movedto z-axis direction to move the metal mask 303 again and the metal mask303 and the substrate 304 are fixed by the auxiliary pins, so that thealignment of the metal mask 303 and the positioning conformation of themetal mask 303 and the substrate 304 can be completed. Incidentally,although the case of positioning conformation by pin-alignment method isdescribed here, positioning conformation may be carried out by CCDalignment method using a CCD camera.

Further, at the time of transporting the substrate from the firsttransportation chamber 301 to the first film formation chamber 305, itis preferable to keep the substrate from the atmospheric air and tomaintain the vacuum degree. Accordingly, before the substratetransportation, the first film formation chamber 305 is made to bevacuum of the extent as same as that of the first transportation chamber301 by the vacuum discharge means.

In FIG. 5, the first film formation chamber 305 is provided with aplurality of deposition sources 306. Each deposition source 306 iscomposed of a material chamber (not illustrated) for storing an organiccompound and a shutter (not illustrated) for controlling the scatteringof the organic compound evaporated in the material chamber to theoutside of the material chamber by opening or closing. Further, thefirst film formation chamber 305 is provided with a substrate heatingmeans. Further, although it is not illustrated, a mechanism for aligningthe substrate heating means and the metal mask 303 (including thesubstrate) is also installed.

A plurality of the deposition sources 306 installed in the first filmformation chamber 305 contain organic compounds having respectivelydifferent functions and composing the organic compound films of a lightemitting element.

In the first film formation chamber 305, the organic compounds stored inthese deposition sources are successively deposited by the methoddescribed in the embodiment 1 or the example 1 to form a first organiccompound film (in this case, red) having a plurality of functionalregions. At the time of deposition, in order to improve the evenness ofthe obtained thin film in the substrate face, film formation is carriedout while the substrate 304 being rotated.

Next, the substrate 304 is transported to a second transportationchamber 307. At the time of transporting the substrate from the firstfilm formation chamber 305 to the second transportation chamber 307, itis preferable to keep the substrate from the atmospheric air and tomaintain the vacuum degree. In the case of using a metal mask with thesame opening pattern, in the second transportation chamber 307, thesubstrate 304 and the metal mask 303 are separated from each other onceand then moved so as to carry out proper positioning for the filmformation of the second organic compound film and the metal mask 303 maybe aligned again. After that, on completion of the alignment, thesubstrate 304 and the metal mask 303 are again overlaid and fixed. Inthe case of using a metal mask with a different pattern, a new mask ispreviously made ready and alignment with the substrate may be carriedout in the second transportation chamber or the second film formationchamber.

Then, the substrate 304 is transported to the second film formationchamber 308. At the time of transporting the substrate from the secondtransportation chamber 307 to the second film formation chamber 308, itis preferable to keep the substrate from the atmospheric air and tomaintain the vacuum degree. The second film formation chamber is alsoprovided with a plurality of deposition sources and substrate heatingmeans and in the same manner in the first film formation chamber 305, aplurality of organic compounds are successively used and deposited toform a second organic compound film (in this case, green) having aplurality of functional regions.

Further, the substrate 304 is transported to a third transportationchamber 309. At the time of transporting the substrate from the secondfilm formation chamber 308 to the third transportation chamber 309, itis preferable to keep the substrate from the atmospheric air and tomaintain the vacuum degree. In the case of using a metal mask with thesame opening pattern, in the third transportation chamber 309, thesubstrate 304 and the metal mask 303 are separated from each other onceand then moved so as to carry out proper positioning for the filmformation of the third organic compound film and the metal mask 303 maybe aligned again. After that, on completion of the alignment, thesubstrate 304 and the metal mask 303 are again overlaid and fixed. Inthe case of using a metal mask with a different pattern, a new mask ispreviously made ready and alignment with the substrate may be carriedout in the third transportation chamber or the third film formationchamber.

Then, the substrate 304 is transported to the third film formationchamber 310. At the time of transporting the substrate from the thirdtransportation chamber 309 to the third film formation chamber 310, itis preferable to keep the substrate from the atmospheric air and tomaintain the vacuum degree. The third film formation chamber is alsoprovided with a plurality of deposition sources and substrate heatingmeans and in the same manner in other formation chambers, a plurality oforganic compounds are successively used and deposited to form a thirdorganic compound film (in this case, blue) having a plurality offunctional regions.

Then, the substrate 304 is transported to an annealing chamber 312. Atthe time of transporting the substrate from the third film formationchamber 310 to the annealing chamber 312, it is preferable to keep thesubstrate from the atmospheric air and to maintain the vacuum degree.After the transportation of the substrate to the annealing chamber 312,annealing in vacuum is carried out. After deposition and the vacuumdegree is further increased than the vacuum degree at the time of thedeposition, annealing at 100 to 200° C. is preferably carried out. Bythe annealing (degassing) the impurities such as oxygen, water and thelike in the organic compound layer formed on the substrate are furtherremoved to form an organic compound layer with a high density and a highpurity. Further, reverse mechanism of the substrate may be provided inanneal chamber 312.

Finally, the substrate 304 is transported to an unload chamber 311 andafter an inert gas is introduced to restore a normal pressure, thesubstrate is taken out of the film formation apparatus.

After an inert gas is introduced in the anneal chamber 312 to restore anormal pressure, the annealing may be carried out. After annealing iscarried out in vacuum in the annealing chamber 312, an inert gas may beintroduced in the anneal chamber 312 to restore a normal pressure.

In such a manner, by carrying out alignment of the metal masks 303 everytime after formation of different organic compound films in therespective transportation chambers (or film formation chambers), aplurality of organic compound films can be formed in a single apparatuswhile the vacuum degree being maintained. As described above, sincefunctional regions forming one organic compound film can be formed in asingle film formation chamber, contamination with impurities among thefunctional regions can be avoided. Further, since this film formationapparatus is capable of forming mixed regions between neighboringfunctional regions, a light emitting element having a plurality offunctions without clear layer structure can be produced.

Although the apparatus which carries out formation of the organiccompound films is described in this example, the film formationapparatus of the invention is not limited to those with thisconstitution but includes those comprising a film formation chamber forforming a cathode on the organic compound films and a treatment chambercapable of sealing the light emitting element. The order of theformation of the organic compound films having the red, green, and blueluminescence may be inconsecutive.

Further, a means for cleaning the transportation chambers and the filmformation chambers shown in this example may be installed. A cleaningpreparatory chamber 22 as shown in FIG. 3 may be also installed.

Further, a mask preparatory chamber for storing used deposition masksand un-used deposition masks may be installed in the respectivetransportation chambers and the respective film formation chambers.

This example may be optionally combined with embodiment 1, embodiment 2,embodiment 3, or example 1.

Example 3

In Example 2, an example of apparatus that forms up through the organiccompound film is described. In this example, an explanation will begiven of the case where the apparatus that conducts to the sealing ofthe present invention is the inline scheme, with reference to FIG. 6.

In FIG. 6, reference numeral 501 denotes a load chamber, from which asubstrate is transported. Note that the term substrate as used in thisexample is to be understood to mean the one with either an anode orcathode (anode used in this example) for use as one electrode of a lightemitting element being formed thereon. In addition the load chamber 501comes with a gas exhaust system 500 a, wherein this exhaust system 500 ais constituted including a first valve 51, a turbo molecular pump 52, asecond valve 53, a third valve 54 and a dry pump 55.

Additionally in this example, as the material used for inside ofrespective processing chambers such as a gate-blocked load chamber, analignment chamber, a deposition chamber, a sealing chamber and anunloading chamber, a material such as aluminum or stainless steel (SUS)with mirror surfaces through treatment of electro polishing is used onthe internal wall planes thereof due to its capability to reduce anadsorption of the impurity such as oxygen and water by making surfacearea of the inside wall smaller. In addition, internal members made ofmaterial such as ceramics or else are employed as the inside materialwhich are treated that pores become extremely less. Note that thesematerials have surface smoothness with the center average roughnessbeing less than or equal to 30 Å.

Although the first valve 51 is a main valve having a gate valve, abutterfly valve that functions also as a conductance valve willalternatively be used. The second valve 53 and the third valve 54 arefore valves. First, a pressure of the load chamber 501 is roughlyreduced by the dry pump 55 with the second valve 53 opened, next, apressure of the load chamber 501 is reduced to a high degree of vacuumby the turbo molecular pump 52 with the first valve 51 and third valve54 open. Note that the turbo molecular pump may be replaced with amechanical booster pump; alternatively, the turbo molecular pump isusable after increased the vacuum degree by the mechanical booster pump.

Next, the one indicated by numeral 502 is an alignment chamber. Here,alignment of a metal mask and positioning of a substrate on the metalmask are done for deposition at a deposition chamber to which it willnext be transferred. The alignment chamber 502 may be equipped with aninversion mechanism of a substrate. Additionally, the method explainedin FIG. 5 may be employed in the alignment method here. Additionally thealignment chamber A502 comprises a gas exhaust system 500 b and is shutand shielded from the load chamber 501 by a gate, not shown.

Further, the alignment chamber A502 is provided with a cleaningpreliminary chamber 513 a to thereby enable of cleanup at the alignmentchamber A502. Note that the used metal mask can be cleanup by providingthe metal mask in the alignment chamber A502 in advance.

Next, numeral 503 denotes a deposition chamber for fabrication of afirst organic compound layer by vacuum evaporation methods, which willbe called deposition chamber A503 hereinafter. The deposition chamberA503 comprises an exhaust system 500 c. In addition, this is shut andshielded from the alignment chamber A502 by a gate, not shown.

In a similar way to the alignment chamber A502, the deposition chamberA503 is provided with a cleaning preliminary chamber 513 b.

In this example, a deposition chamber that has the structure shown inFIG. 1 is provided as the deposition chamber A503 for fabrication of thefirst organic compound layer which emits red light. Additionallyprovided as the evaporation sources are a first evaporation sourceprovided with an organic compound with hole injectability, a secondevaporation source provided with an organic compound with holetransportability, a third evaporation source provided with an organiccompound with hole transportability for use as a host of organiccompound with luminescent ability, a fourth evaporation source providedwith an organic compound with luminescent ability, a fifth evaporationsource provided with an organic compound with blocking ability, and asixth evaporation source provided with an organic compound with electrontransportability.

It is also noted that in this example, copper phthalocyanine(abbreviated as “Cu—Pc” hereinafter) is used as the organic compoundwith hole injectability that provided in the first evaporation source;4,4′-bis [N-(1-naphthyl)-N-phenyl-amino]-biphenyl (abbreviated as“α-NPD” hereafter) is used as the organic compound with holetransportability being provided in the second evaporation source;4,4′-dicarbazole-biphenyl (“CBP”) is used as the organic compound whichbecomes the host provided in the third evaporation source;2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin-platinum (“PtOEP”) isused as the organic compound with luminescent ability provided in thefourth evaporation source; bathocuproin (“BCP”) is used as the organiccompound with blocking ability provided in the fifth evaporation source;and, tris (8-quinolinolat) aluminum (“Alq₃”) is used as the organiccompound with electron transportability provided in the sixthevaporation source.

It is noted that the organic compound layer comprising regions havingthe functions of hole injectability, hole transportability, luminescentability, and electron transportability can be formed over the anode bydepositing these organic compound in order through a vacuum evaporation.

Also note that in this example, a mixed region is formed at an interfacebetween different function regions by simultaneous vacuum evaporation oforganic compounds consisting of both function regions. To be brief,mixed regions are formed respectively at an interface between the holeinjection region and the hole transport region and at an interfacebetween the hole transport region and the electron transport regionincluding a luminescent region.

Practically, after formed a first function region through deposition ofCu—Pc to a thickness of 15 nm, both Cu—Pc and α-NPD are deposited by avacuum evaporation at a same time to thereby form a first mixed regionwith a film thickness of 5 to 10 nm. Then, fabricate a film of α-NPD toa thickness of 40 nm to thereby form a second function region, followedby formation of a second mixed region with a thickness of 5 to 10 nm bysimultaneous vacuum evaporation of α-NPD and CBP. Thereafter, fabricatea film of CBP to a thickness of 25 to 40 nm, thus forming a thirdfunction region. At the step of forming the third function region, bothCBP and PtOEP are deposited at a same time, thereby forming a thirdmixed region at the entirety or part of the third function region. Notehere that the third mixed region has luminescent ability. Further, bothCBP and BCP are deposited by simultaneous vacuum evaporation to a filmthickness of 5 to 10 nm, thereby forming a fourth mixed region. Inaddition, a BCP film is fabricated to a thickness of 8 nm, thus forminga fourth function region. Furthermore, BCP and Alq₃ are deposited bysimultaneous vacuum evaporation to a film thickness of 5 to 10 nm,resulting in formation of a fifth mixed region. Lastly a film of Alq₃ isformed to a thickness of 25 nm, thus enabling formation of a fifthfunction region. With the above process steps, a first organic compoundlayer is thus formed.

It should be noted that in the above explanation concerning the firstorganic compound layer six kinds of organic compounds different infunction from one another are provided in six evaporation sourcesrespectively and the organic compound layer is then formed by vacuumevaporation of these organic compounds. This example should not belimited only to the above and may use a plurality of organic compounds.Additionally the organic compound provided in a single evaporationsource should not always be limited to a single one and mayalternatively be multiple ones. For example, in addition to a singlekind of material provided in an evaporation source as an organiccompound with luminescent ability, another organic compound that serveas a dopant may be provided together. Note that the first organiccompound layer has a plurality of functions and prior known materialsmay be used as these organic compounds composing an organic compoundlayer which emits the red light.

It is to be noted that the evaporation sources may be designed so that amicrocomputer is used to control the deposition speeds thereof.Additionally, with this arrangement, it is preferable to control theratio of mixture upon simultaneous fabrication of a plurality of organiccompound layers.

Next, the one indicated by numeral 506 is an alignment chamber. Here,alignment of a metal mask and positioning of a substrate on the metalmask are done for deposition at a deposition chamber to which it willnext be transferred. The alignment may be done in the deposition chamber507. Additionally the alignment chamber B506 comprises a gas exhaustsystem 500 d and is shut and shielded from the deposition chamber A503by a gate not shown. It further comprises a cleaning preliminary chamber513 c that is shut and shielded from the alignment chamber B506 by agate not shown, in a similar way to the alignment chamber A502.

Next, numeral 507 denotes a deposition chamber for fabrication of asecond organic compound layer by vacuum evaporation, which will becalled the deposition chamber B507. This deposition chamber B507 isprovided with an exhaust system 500 e. In addition it is shut andshielded from the alignment chamber B506 by a gate, not shown. Further,it comprises a cleaning preliminary chamber 513 d which is shut andshielded from the deposition chamber B507 by a gate not shown, in asimilar way to the deposition chamber A503.

In this example a deposition chamber with the structure shown in FIG. 1is provided as the deposition chamber B507 for fabrication of a secondorganic compound layer which emits green light. Additionally provided asthe evaporation sources are a first evaporation source provided with anorganic compound with hole injectability, a second evaporation sourceand a third evaporation source each provided with organic compounds withhole transportability, a fourth evaporation source provided with a hostmaterial with hole transportability, a fifth evaporation source providedwith an organic compound with luminescent ability, a sixth evaporationsource provided with an organic compound with blocking ability, and aseventh evaporation source provided with an organic compound withelectron transportability.

It is noted that in this example, Cu—Pc is employed as the organiccompound with hole injectability provided in the first evaporationsource; MTDATA is employed as the organic compound with holetransportability provided in the second evaporation source; α-NPD isemployed as the organic compound with hole transportability provided inthe third evaporation source; CBP is employed as the host material withhole transportability provided in the fourth evaporation source; tris(2-phenylpyridine) iridium (Ir(ppy)₃) is employed as the organiccompound with luminescent ability provided in the fifth evaporationsource; BCP is employed as the organic compound with blocking abilityprovided in the sixth evaporation source; and, Alq₃ is employed as theorganic compound with electron transportability provided in the seventhevaporation source.

It is noted the second organic compound layer can be formed on the anodeby successive vacuum evaporation of these organic compounds, whichcomprises regions having functions of hole transportability, luminescentability, blocking ability and electron transportability.

Also note that in this example, a mixed region is formed at an interfacebetween different function regions by simultaneous vacuum evaporation oforganic compounds forming both the function regions. More specifically,mixed regions are formed respectively at an interface between the holetransport region and the blocking region and at an interface between theblocking region and the electron transport region.

Practically, after formed a first function region through deposition ofCu—Pc to a thickness of 10 nm, both Cu—Pc and MTDATA are deposited by avacuum evaporation at a same time to thereby form a first mixed regionwith a film thickness of 5 to 10 nm. Then, fabricate a film of MTDATA toa thickness of 20 nm to thereby form a second function region, followedby formation of a second mixed region with a thickness of 5 to 10 nm bysimultaneous vacuum evaporation of MTDATA and α-NPD. Thereafterfabricate a film of α-NPD to a thickness of 10 nm, thereby forming athird function region. Then, by simultaneous vacuum evaporation of α-NPDand CBP, a third mixed region is formed in thickness from 5 to 10 nm.Subsequently, fabricate a film of CBP to a thickness of 20 to 40 nm tothereby form a fourth function region. At the step of forming the fourthfunction region, (Ir(ppy)₃) is deposited by simultaneous vacuumevaporation at part or entirety of the fourth function region, thusforming a fourth mixed region; then, simultaneously deposited CBP andBCP by vacuum evaporation to form a fifth mixed region with a thicknessof 5 to 10 nm; next, deposit a BCP film of 10 nm thickness to therebyform a fifth function region; next, simultaneously deposit BCP and Alq₃by vacuum evaporation to form a sixth mixed region with a film thicknessof 5 to 10 nm; lastly, form a film of Alq₃ to a thickness of 40 nm, thusforming a sixth function region to thereby form a second organiccompound layer.

Noted that in the above explanation the organic compound layer is formedby vacuum evaporation from seven evaporation sources provided withorganic compounds having different functions respectively as the secondorganic compound layer. This example should not be limited only to theabove and is modifiable as far as a plurality of evaporation sources.Additionally prior known materials may be used as organic compounds witha plurality of functions for forming an organic compound layer whichemits green light.

Next, the one indicated by numeral 508 is an alignment chamber. Here,alignment of a metal mask and positioning of a substrate on the metalmask are done for deposition at a deposition chamber to which it willnext be transferred. The alignment may be done in the deposition chamber509. Additionally the alignment chamber C508 comprises a gas exhaustsystem 500 f and is shut and shielded from the deposition chamber B507by a gate not shown. It further comprises a cleaning preliminary chamber513 e that is shut and shielded from the alignment chamber C508 by agate not shown, in a similar way to the alignment chamber A502.

Next, numeral 509 denotes a deposition chamber for fabrication of athird organic compound layer by vacuum evaporation, which will be calledthe deposition chamber C509. This deposition chamber C509 is providedwith an exhaust system 500 g. In addition it is shut and shielded fromthe alignment chamber C508 by a gate not shown. Further, it comprises acleaning preliminary chamber 513 f which is shut and shielded from thedeposition chamber C509 by a gate not shown, in a similar way to thealignment chamber A503.

In this example a deposition chamber with the structure shown in FIG. 1is provided as the deposition chamber C509 for fabrication of a thirdorganic compound layer which emits blue light. Additionally provided asthe evaporation sources are a first evaporation source provided with anorganic compound with hole injectability, a second evaporation sourceprovided with organic compound with luminescent ability, a thirdevaporation source provided with blocking ability, a fourth evaporationsource provided with an organic compound with electron transportability.

It is noted that in this example, Cu—Pc is employed as the organiccompound with hole injectability provided in the first evaporationsource; α-NPD is employed as the organic compound with luminescentability provided in the second evaporation source; BCP is employed asthe organic compound with blocking ability provided in the thirdevaporation source; and, Alq₃ is employed as the organic compound withelectron transportability provided in the fourth evaporation source.

It is noted the third organic compound layer can be formed over theanode by successive vacuum evaporation of these organic compounds, whichcomprises regions having functions of hole injectability, luminescentability, blocking ability and electron transportability.

Also note that in this example, a mixed region is formed at an interfacebetween different function regions by simultaneous vacuum evaporation oforganic compounds forming both the function regions. More specifically,mixed regions are formed respectively at an interface between the holeinjection region and the light emitting region, the light emittingregion and the blocking region, and the blocking region and the electrontransport region.

Practically, after formed a first function region through deposition ofCu—Pc to a thickness of 20 nm, both Cu—Pc and α-NPD are deposited by avacuum evaporation at a same time to thereby form a first mixed regionwith a film thickness of 5 to 10 nm. Then, fabricate a film of α-NPD toa thickness of 40 nm to thereby form a second function region, followedby formation of a second mixed region with a thickness of 5 to 10 nm bysimultaneous vacuum evaporation of α-NPD and BCP. Thereafter fabricate afilm of BCP to a thickness of 10 nm, thereby forming a third functionregion. Then, by simultaneous vacuum evaporation of BCP and Alq₃, athird mixed region is formed in thickness from 5 to 10 nm; lastly, forma film of Alq₃ to a thickness of 40 nm, to thereby form a third organiccompound layer.

Noted that in the above explanation the organic compound layer is formedby successive vacuum evaporation from fourth evaporation sourcesprovided with four organic compounds having different functionsrespectively as the third organic compound layer. The present inventionshould not be limited only to the above and is modifiable as far as aplurality of evaporation sources. Also, an organic compound provided ina single evaporation source is not limited to have one kind, may be aplurality of ones. For instance, in addition to a single kind ofmaterial provided in an evaporation source as the organic compound withluminescent ability, another organic compound that serve as a dopant maybe provided together. Note that prior known materials may be used asorganic compounds with a plurality of functions for forming an organiccompound layer which emits blue light.

Additionally in this example, one specific case has been explained wherethe organic compound layer which emits red light is formed in the firstdeposition chamber A503 while forming the organic compound layer whichemits green light in the second deposition chamber B507 and also formingthe organic compound layer which emits blue light in the thirddeposition chamber C509. However, the order of formation of these layersshould not be limited only the above order. One of the organic compoundlayers which emit lights of red, green, and blue, respectively may beformed within one of the deposition chamber A503, deposition chamberB507, and deposition chamber C509. Still alternatively, an additionaldeposition chamber may be provided for forming an organic compound layerwhich emits white light therein.

An annealing furnace may be provided to anneal the organic compound filmwith vacuum after the deposition of the organic compounds. By theannealing after the deposition, oxygen and water in the organic compoundlayer formed on the substrate is removed further so that high-densityand high-purity organic compound layer may be formed.

Next, numeral 510 denotes a deposition chamber for formation of aconductive film being either the anode or the cathode of a lightemitting element (a metal film used as the cathode in this example) byvacuum evaporation, which will be called the deposition chamber D510.The deposition chamber D510 comprises an exhaust system 500 h, inaddition, is shut and shielded from the deposition chamber C509 by agate not shown. Further, it comprises a cleaning preliminary chamber 513g which is sealed and shielded from the deposition chamber D510 by agate not shown, in a similar manner to that of the deposition chamberA503.

In this example a deposition chamber with the structure shown in FIG. 1is provided as the deposition chamber D510. Accordingly, in regard to adetailed operation of the deposition chamber D510, refer to theexplanation of FIG. 1.

In this example, in the deposition chamber D510, an Al—Li alloy film(film made of an alloy of aluminum and lithium) is deposited as theconductive film used as the cathode of the light emitting element.Additionally it will also possible to employ co-vacuum evaporation ofaluminum and an element belonging to either the group I or group II ofthe periodic table.

Alternatively a CVD chamber may be provided here for formation of aninsulating film such as a silicon nitride film, silicon oxide film andDLC film or else as a protective film (passivation film) of the lightemitting element. Note that in the case of providing such CVD chamber,it will be preferable that a gas purifying machine be provided forincreasing in advance the purity of a material gases used in the CVDchamber.

Next, numeral 511 denotes a sealing chamber, which comprises an exhaustsystem 500 i. In addition, it is shut and shielded from the depositionchamber D510 by a gate not shown. In the seal chamber 511, processing isto be done for finally enclosing a light emitting element in a sealedspace. This processing is the treatment for protecting the lightemitting element formed against oxygen and water, and employs a meansfor mechanically enclosing it by a cover material or alternatively forenclosing it by either thermally hardenable resin or ultraviolet-rayhardenable resin material.

While the cover material used may be glass, ceramics, plastic or metal,the cover material must have optical transmissivity in cases where lightis emitted toward the cover material side. Additionally the covermaterial and a substrate with the above-stated light emitting elementformed thereon are adhered together by use of a seal material such asthermal hardenable resin or ultraviolet-ray hardenable resin or else,thereby forming an air-tight sealed space by letting the resin behardened through thermal processing or ultraviolet ray irradiationprocessing. It is also effective to provide in this sealed space amoisture absorbable material, typical example of which is barium oxide.

It will also be possible to fill the space between the cover materialand the substrate having the light emitting element formed thereon witheither thermal hardenable resin or ultraviolet-ray hardenable resin. Inthis case, it is effective to add a moisture absorption materialtypically such as barium oxide into either the thermal hardenable resinor ultraviolet-ray hardenable resin.

In the deposition apparatus shown in FIG. 6, a mechanism for irradiationof ultraviolet light to the interior of the seal chamber 511 (referredto as the “ultraviolet light irradiation mechanism” hereinafter) isprovided, which is arranged so that ultraviolet light as emitted fromthis ultraviolet light irradiation mechanism is used to harden theultraviolet-ray hardenable resin.

Lastly, numeral 512 is an unload chamber, which comprises an exhaustsystem 500 j. The substrate with light emitting element formed thereonwill be taken out of here.

As described the above, by using the deposition apparatus shown in FIG.6 or FIG. 1, exposure of the light emitting element to the outside airis avoided until the light emitting element is completely enclosed inthe sealed space. Thus, it is possible to manufacture a luminescentdevice with high reliability.

This example may be freely combined with Embodiment 1 to 3, Examples 1,or Example 2.

Example 4

Another film formation apparatus of the invention will be described withthe reference to FIG. 7. In FIG. 7, the numeral 701 denotes atransportation chamber and the transportation chamber 701 is providedwith a transportation mechanism (A) 702 and transports a substrate 703.The transportation chamber 701 is controlled to be in decreased pressureatmosphere and connected with respective treatment chambers throughgates. Sending and receiving a substrate to and from the respectivechambers is carried out by the transportation mechanism (A) 702 when thegates are opened. Further, to decrease the pressure in thetransportation chamber 701, a gas evacuation pump such as a dry pump,mechanical booster pump, turbo-molecular pump (a magnetically floatingtype) or a cryopump can be employed and in order to produce highlyvacuum state with a high purity, the magnetically floating typeturbo-molecular pump is preferable.

Hereinafter, the respective treatment chambers will be described.Incidentally, since the transportation chamber 701 is in decreasedpressure atmosphere, the treatment chambers directly connected to thetransportation chamber 701 are all equipped with gas discharge pumps(not illustrated). As the gas evacuation pumps, the above-mentioned drypump, mechanical booster pump, turbo-molecular pump (a magneticallyfloating type) or cryopump can be employed and also in this case, themagnetically floating type turbo-molecular pump is preferable.

At first, the numeral 704 denotes a load chamber for carrying outsetting (disposing) a substrate. The load chamber 704 is connected tothe transportation chamber 701 through a gate 700 a and a carrier (notillustrated) on which the substrate 703 is mounted is installed here.The load chamber 704 works also as a transportation chamber for asubstrate which is passed through the element formation process to asealing chamber. The load chamber 704 may comprise different rooms forsubstrate transporting in and substrate transporting out. Further, theload chamber 704 is provided with the above-mentioned gas discharge pumpand a purge line for introducing nitrogen gas or a rare gas with a highpurity. Turbo molecular pump is preferable for gas discharge pump.Further, the purge line is equipped with a gas refining apparatus so asto previously remove impurities (oxygen and water) from the gas to beintroduced into the apparatus.

In this example, as the substrate 703, a substrate on which atransparent conductive film to be an anode of a light emitting elementis employed. In this example, the substrate 703 is set on the carrierwhile the face to form a film thereon being face down.

Next, the numeral 705 denotes an alignment chamber for carrying outalignment of a metal mask and positioning conformation of the substratepassed through the formation of an anode or a cathode (in this case, ananode) of the light emitting element and the metal mask and thealignment chamber 705 is connected to the transportation chamber 701through a gate 700 b. Incidentally, every time different organiccompound films are formed, alignment of the metal mask and positioningconformation of the substrate and the metal mask are carried out in thealignment chamber. Further, in the alignment chamber 705, a CCD (acharge coupled device) known as an image sensor is installed, so thatpositioning conformation of the substrate and the metal mask can becarried out at a high precision at the time of film formation using themetal mask.

Further, a cleaning preparatory chamber 722 a is connected to thealignment chamber 705. The constitution of the cleaning preparatorychamber 722 a is as shown in FIG. 3 and the embodiment 2. Cleaning maybe carried out using a reactive gas. Alternatively, no cleaningpreparatory chamber is installed and as shown in the embodiment 3, a gas(one or a plurality of types of gases selected from Ar, H, F, NF₃, andO) is introduced into the film formation chamber and plasma is generatedin the film formation chamber to carry out dry cleaning or Ar gas or thelike is introduced and physical cleaning by sputtering method may becarried out.

In the case of carrying out cleaning using the reactive gas, a μ waveoscillator for generating μ wave is installed and the μ wave generatedthere is transmitted to a plasma discharge tube through a waveguide.Incidentally, from the μ wave oscillator to be employed in this case, μwave of about 2.45 GHz is radiated. Further, to the plasma dischargetube, the reactive gas is supplied from a gas introduction pipe. As thereactive gases NF₃, CF₄, or ClF₃ may be used. The reactive gas isdecomposed by the μ wave in the plasma discharge tube and radical isgenerated. The radical passes through the gas introduction pipe and isintroduced into the alignment chamber 705 connected to through the gate.In the alignment chamber 705, a metal mask bearing an organic compoundfilm is previously disposed. Then, the radical can be introduced intothe alignment chamber 705 by opening the gate installed between thecleaning preparatory chamber 722 a and the alignment chamber 705.Consequently, cleaning of the metal mask can be carried out.

Next, the numeral 706 is a film formation chamber for forming an organiccompound film by a deposition method and named as a film formationchamber (A). The film formation chamber (A) 706 is connected to atransportation chamber 701 through a gate 700 c. In this example, a filmformation chamber with a structure shown in FIG. 1 is formed as the filmformation chamber (A) 706.

In this example, in a film formation part 707 in the film formationchamber (A) 706, a first organic compound film emitting red color isformed.

By successively depositing organic compounds, an organic compound filmcomprising regions having functional properties of a hole injectingproperty, a hole transporting property, a light emitting property, andan electron transporting property can be formed.

The film formation chamber (A) 706 is connected to a materialreplacement chamber 714 through a gate 700 g. In the materialreplacement chamber 714, a heater for heating the replacing organiccompound is installed. Impurities such as water can be removedpreviously by heating the organic compound. The temperature at the timeof heating is preferably 200° C. or lower. Further, since the materialreplacement chamber 714 is provided with a gas discharge pump capable ofkeeping the inside in decreased pressure, the inside is kept indecreased pressure after an organic compound is additionally suppliedfrom the outside or exchanged and then heated. When the pressure isdecreased to the same level as that of the film formation chamber, thegate 700 g is opened to supplement the organic compound to thedeposition source in the inside of the film formation chamber. Theorganic compound is thus stored in the deposition source in the filmformation chamber by the transportation mechanism.

Regarding the film formation process in the film formation chamber (A)706, the description of FIG. 1 described in the embodiment 1 and theexample 1 should be referred to.

Incidentally, similarly to the alignment chamber 705, a cleaningpreparatory chamber 722 b is connected also to the film formationchamber (A) 706 through a gate (not illustrated). The practicalconstitution is same as the cleaning preparatory chamber 722 a andorganic compound or the like adhering to the inside of the filmformation chamber (A) 706 can be removed.

Next, the numeral 708 denotes a film formation chamber for forming asecond organic compound film by a deposition method and named as a filmformation chamber (B). The film formation chamber (B) 708 is connectedto a transportation chamber 701 through a gate 700 d. In this example, afilm formation chamber with a structure shown in FIG. 1 is formed as thefilm formation chamber (B) 708. In this example, in a film formationpart 709 in the film formation chamber (B) 708, an organic compound filmemitting green color is formed.

By successively depositing organic compounds, an organic compound filmcomprising regions having functional properties of a hole transportingproperty, a light emitting property, a blocking property and an electrontransporting property can be formed.

The film formation chamber (B) 708 is connected to a materialreplacement chamber 715 through a gate 700 h. In the materialreplacement chamber 715, a heater for heating the replacing organiccompound is installed. Impurities such as water can be removedpreviously by heating the organic compound. The temperature at the timeof heating is preferably 200° C. or lower. Further, since the materialreplacement chamber 715 is provided with a gas discharge pump capable ofkeeping the inside in decreased pressure, the inside is kept indecreased pressure after an organic compound is introduced into from theoutside. When the pressure is decreased to the same level as that of thefilm formation chamber, the gate 700 h is opened to supplement theorganic compound to the deposition source in the inside of the filmformation chamber. The organic compound is thus stored in the depositionsource in the film formation chamber by the transportation mechanism orthe like.

Regarding the film formation process in the film formation chamber (B)708, the description of FIG. 1 described in the embodiment 1 and theexample 1 should be referred to. Incidentally, similarly to thealignment chamber 705, a cleaning preparatory chamber 722 c is connectedalso to the film formation chamber (B) 708 through a gate (notillustrated).

Next, the numeral 710 denotes a film formation chamber for forming athird organic compound film by a deposition method and named as a filmformation chamber (C). The film formation chamber (C) 710 is connectedto a transportation chamber 701 through a gate 700 e. In this example, afilm formation chamber with a structure shown in FIG. 1 is formed as thefilm formation chamber (C) 710. In this example, in a film formationpart 711 in the film formation chamber (C) 710, an organic compound filmemitting blue color is formed.

By successively depositing organic compounds, an organic compound filmcomprising regions having functional properties of a hole injectingproperty, a light emitting property, a blocking property and an electrontransporting property can be formed.

The film formation chamber (C) 710 is connected to a materialreplacement chamber 716 through a gate 700 i.

Regarding the film formation process in the film formation chamber (C)710, the description of FIG. 1 described in the embodiment 1 and theexample 1 should be referred to. Incidentally, similarly to thealignment chamber 705, a cleaning preparatory chamber 722 d is connectedalso to the film formation chamber (C) 710 through a gate (notillustrated).

Next, the numeral 712 denotes a film formation chamber for forming aconductive film to be an anode or a cathode (in this example, a metalfilm to be a cathode) of a light emitting element by a deposition methodand named as a film formation chamber (D). The film formation chamber(D) 712 is connected to the transportation chamber 701 through a gate700 f. In this example, in a film formation part 713 in the filmformation chamber (D) 712, an Al—Li alloy film (alloy film of Aluminumand Lithium) to be a conductive film of a cathode of the light emittingelement is formed. Incidentally, elements belonging to group I or groupII in a periodic table may be co-deposited with aluminum.

The film formation chamber (D) 712 is connected to a materialreplacement chamber 717 through a gate 700 j. In the materialreplacement chamber 717, a heater for heating the replacing conductivematerial is installed. Incidentally, similarly to the alignment chamber705, a cleaning preparatory chamber 722 e is connected also to the filmformation chamber (D) 712 through a gate (not illustrated).

Further, heating mechanism for heating the respective film formationchambers is installed in each of the film formation chamber (A) 706, thefilm formation chamber (B) 708, the film formation chamber (C) 710 andthe film formation chamber (D) 712. Consequently, some of the impuritiesin the respective chambers can be removed.

Further, each of the film formation chamber (A) 706, the film formationchamber (B) 708, the film formation chamber (C) 710 and the filmformation chamber (D) 712 is kept in decreased pressure by a gasdischarge pump. Incidentally, the achieved vacuum degree in this case ispreferably 10-6 Pa or higher and for example, amount of leakage shouldbe 4.1×10⁻⁷ Pa.m³/s⁻¹ or lower for 20 hours in the case of using acryopump of a gas discharge speed of 10,000 l/s (H₂O), setting thesurface area 10 m² of the inside of each film formation chamber andusing aluminum to form the inside of the film formation chamber.

Next, the numeral 718 denotes a sealing chamber (referred also to as asealing chamber or a globe box) and connected to the load chamber 704through a gate 700 k. In the sealing chamber 718, a treatment forfinally sealing the light emitting element in a closed space is carriedout. The treatment is for protecting the formed light emitting elementfrom oxygen and water and sealing it mechanically with a cover materialor by employing means of sealing with a thermosetting resin or a UVcurable resin.

As the cover material, glass, ceramics, plastics or metals may beemployed, however in the case light is radiated to the cover materialsside, it should be light transmissive. Further, the cover material andthe substrate on which the above-mentioned light emitting element isformed are stuck to each other by using a sealing agent of athermosetting resin or a UV curable resin and the closed space can beformed by curing the resin by heating treatment or UV radiationtreatment. It is also effective to put an absorbent such as barium oxidein the closed space.

Further, the space between the cover material and the substrate on whichthe above-mentioned light emitting element is formed may be filled witha thermosetting resin or a UV curable resin. In such a case, it is alsoeffective to put an absorbent such as barium oxide in the closed space.

In the film formation apparatus shown in FIG. 7, mechanism (hereinafterreferred to as UV radiation mechanism) 719 for radiating UV rays isinstalled in the inside of the sealing chamber 718 and the UV curableresin is cured by UV rays radiated from the UV radiation mechanism 719.The inside of the sealing chamber 718 may be kept in vacuum byinstalling a gas discharge pump. In the case where the above-mentionedsealing process is carried out mechanically by robot operation,contamination with oxygen and water can be prevented by carrying out theprocess in vacuum condition. Practically the concentration of oxygen andwater is preferably decreased to 0.3 ppm or lower. On the contrary, theinside of the sealing chamber 718 may be pressurized. In this case, thepressure is applied while purging with a highly pure nitrogen gas orrare gas so as to prevent penetration of oxygen from the outside air.

Next, a passing chamber (a pass box) 720 is connected to the sealingchamber 718. The passing chamber 720 is provided with a transportationmechanism (B) 721 and the substrate passed through the sealing treatmentof the light emitting element in the sealing chamber 718 is transportedto the passing chamber 720. The passing chamber 720 is also made to bevacuum by installing a gas discharge pump. The passing chamber 720 is afacility for inhibiting the sealing chamber 718 from direct exposure tothe atmospheric air and from the chamber, the obtained substrate istaken out. Besides, a member supply chamber (not illustrated) forsupplying a member to be employed in the sealing chamber may beinstalled.

Although it is not illustrated in this example, after the light emittingelement formation, an insulating film of a compound containing siliconnitride, silicon oxide or the like or an insulating film comprising acarbon-containing DLC (diamond like carbon) layered further thereonmaybe formed on the light emitting element. The DLC (diamond likecarbon) film means an amorphous film in which diamond bond (SP³ bond)and graphite bond (SP² bond) exist together. Further, in this case, afilm formation chamber provided with a CVD (chemical vapor deposition)apparatus for forming a thin film by generating plasma by applyingself-bias and decomposing raw material gases by plasma discharge may beinstalled.

As described above, by employing the film formation apparatus shown inFIG. 7, without being exposed to the atmospheric air, the processes canbe carried out until the light emitting element is completely sealed inthe closed space, so that a highly reliable light emitting apparatus canbe produced.

The example can be optically combined with embodiment 1, embodiment 2,example 1 or example 2.

Example 5

Here, a detailed description will be given on a light emitting device byusing the deposition apparatus of the present invention. FIG. 8 is across-sectional view of the active matrix type light emitting device. Asan active element, a thin film transistor is used (hereinafter referredto as TFT) here, a MOS transistor may also be used.

A top gate TFT (specifically a planar TFT) is shown as an example, abottom gate TFT (typically inversely staggered TFT) may also be used.

In this example, a substrate 800 is used, which is made of bariumborosilicate glass or aluminoborosilicate glass, a quartz substrate, asilicon substrate, a metal substrate, or stainless substrate forming aninsulating film on the surface may be used. A plastic substrate havingheat resistance enduring a treatment temperature of this example alsomay be used, and further a flexible substrate may be used.

Next, a silicon oxynitride film is formed as a lower layer 801 of a baseinsulating film on a heat-resistant glass substrate (the substrate 800)with a thickness of 0.7 mm by plasma CVD at a temperature of 400° C.using SiH₄, NH₃, and N₂O as material gas (the composition ratio of thesilicon oxynitride film: Si=32%, O=27%, N=24%, H=17%). The siliconoxynitride film has a thickness of 50 nm (preferably 10 to 200 nm). Thesurface of the film is washed with ozone water and then an oxide film onthe surface is removed by diluted fluoric acid (diluted down to{fraction (1/100)}). Next, a silicon oxynitride film is formed as anupper layer 802 of the base insulating film by plasma CVD at atemperature of 400° C. using SiH₄ and N₂O as material gas (thecomposition ratio of the silicon oxynitride film: Si=32%, O=59%, N=7%,H=2%). The silicon oxynitride film has a thickness of 100 nm (preferably50 to 200 nm) and is laid on the lower layer to form a laminate. Withoutexposing the laminate to the air, a semiconductor film having anamorphous structure (here, an amorphous silicon film) is formed on thelaminate by plasma CVD at a temperature of 300° C. using SiH₄ asmaterial gas. The semiconductor film (an amorphous silicon film is usedhere) is 54 nm (preferably 25 to 200 nm) in thickness.

A base insulating film in this example has a two-layer structure.However, the base insulating film may be a single layer or more than twolayers of insulating films mainly containing silicon. The material ofthe semiconductor film is not limited but it is preferable to form thesemiconductor film from silicon or a silicon germanium alloy(Si_(x)Ge_(1-X) (X=0.0001 to 0.02)) by a known method (sputtering,LPCVD, plasma CVD, or the like). Plasma CVD apparatus used may be onethat processes wafer by wafer or one that processes in batch. The baseinsulating film and the semiconductor film may be formed in successionin the same chamber to avoid contact with the air.

The surface of the semiconductor film having an amorphous structure iswashed and then a very thin oxide film, about 2 nm in thickness, isformed on the surface using ozone water. Next, the semiconductor film isdoped with a minute amount of impurity element (boron or phosphorus) inorder to control the threshold of the TFTs. Here, the amorphous siliconfilm is doped with boron by ion doping in which diborane (B₂H₆) isexcited by plasma without mass separation. The doping conditions includesetting the acceleration voltage to 15 kV, the flow rate of gas obtainedby diluting diborane to 1% with hydrogen to 30 sccm, and the dose to2×10¹² atoms/cm².

Next, a nickel acetate solution containing 10 ppm of nickel by weight isapplied by a spinner. Instead of application, nickel may be sprayed ontothe entire surface by sputtering.

The semiconductor film is subjected to heat treatment to crystallize itand obtain a semiconductor film having a crystal structure. The heattreatment is achieved in an electric furnace or by irradiation ofintense light. When heat treatment in an electric furnace is employed,the temperature is set to 500 to 650° C. and the treatment lasts for 4to 24 hours. Here, a silicon film having a crystal structure is obtainedby heat treatment for crystallization (at 550° C. for 4 hours) afterheat treatment for dehydrogenation (at 500° C. for an hour). Althoughthe semiconductor film is crystallized here by heat treatment using anelectric furnace, it may be crystallized by a lamp annealing apparatuscapable of achieving crystallization in a short time.

After an oxide film on the surface of the silicon film having a crystalstructure is removed by diluted fluoric acid or the like, a continuouswave solid-state laser and the second to fourth harmonic of thefundamental wave are employed in order to obtain crystals of large grainsize when crystallizing an amorphous semiconductor film. Since the laserlight irradiation is conducted in the air or in an oxygen atmosphere, anoxide film is formed on the surface as a result. Typically, the secondharmonic (532 nm) or third harmonic (355 nm) of a Nd:YVO₄ laser(fundamental wave: 1064 nm) is employed. When using a continuous wavelaser, laser light emitted from a 10 W power continuous wave YVO₄ laseris converted into harmonic by a non-linear optical element.Alternatively, the harmonic is obtained by putting a YVO₄ crystal and anon-linear optical element in a resonator. The harmonic is preferablyshaped into oblong or elliptical laser light on an irradiation surfaceby an optical system and then irradiates an irradiation object. Theenergy density required at this point is about 0.01 to 100 MW/cm²(preferably 0.1 to 10 MW/cm²). During the irradiation, the semiconductorfilm is moved relative to the laser light at a rate of 10 to 2000 cm/s.

Of course, although a TFT can be formed by using the silicon film havinga crystallizing structure before the second harmonics of the continuouswave YVO₄ laser is irradiated thereon, it is preferable that the siliconfilm having a crystalline structure after the laser light is irradiatedthereon is used to form the TFT since the silicon film irradiated thelaser light thereon has an improved crystallinity and electriccharacteristics of TFT are improved. For instance, although, when TFT isformed by using the silicon film having a crystalline structure beforethe laser light is irradiated thereon, a mobility is almost 300 cm²/Vs,when TFT is formed by using the silicon film having a crystallinestructure after the laser light is irradiated thereon, the mobility isextremely improved with about 500 to 600 cm²/Vs.

After the crystallization is conducted using nickel as a metal elementthat promotes crystallization of silicon, the continuous wave YVO₄ laseris irradiated thereon though, not limited thereof, after the siliconfilm is formed having an amorphous structure and the heat treatment isperformed for dehydrogenation, and the silicon film having a crystallinestructure may be obtained by the second harmonics of the continuous waveYVO₄ laser is irradiated.

The pulse wave laser may be used for as a substitute for the continuouswave laser. In the case that the excimer laser of the pulse wave isused, it is preferable that the frequency is set to 300 Hz, and thelaser density is set from 100 to 1000 mJ/cm² (typically 200 to 800mJ/cm²). Here, the laser light may be overlapped 50 to 98%.

The oxide film formed by laser light irradiation is removed by dilutedfluoric acid and then the surface is treated with ozone water for 120seconds to form as a barrier layer an oxide film having a thickness of 1to 5 nm in total. The barrier layer here is formed using ozone water butit may be formed by oxidizing the surface of the semiconductor filmhaving a crystal structure through ultraviolet irradiation in an oxygenatmosphere, or formed by oxidizing the surface of the semiconductor filmhaving a crystal structure through oxygen plasma treatment, or by usingplasma CVD, sputtering or evaporation to form an about 1 to 10 nm thickoxide film. The oxide film formed by the laser light irradiation may beremoved before the barrier layer is formed.

Next, an amorphous silicon film containing argon is formed on thebarrier layer by plasma CVD or sputtering to serve as a gettering site.The thickness of the amorphous silicon film is 50 to 400 nm, here 150nm. The amorphous silicon film is formed in an argon atmosphere with thefilm formation pressure to 0.3 Pa by sputtering using the silicontarget.

Thereafter, heat treatment is conducted in an electric furnace at 650°C. for 3 minutes for gettering to reduce the nickel concentration in thesemiconductor film having a crystal structure. Lamp annealing apparatusmay be used instead of an electric furnace.

Using the barrier layer as an etching stopper, the gettering site,namely, the amorphous silicon film containing argon, is selectivelyremoved. Then, the barrier layer is selectively removed by dilutedfluoric acid. Nickel tends to move toward a region having high oxygenconcentration during gettering, and therefore it is desirable to removethe barrier layer that is an oxide film after gettering.

Next, a thin oxide film is formed on the surface of the obtained siliconfilm containing a crystal structure (also referred to as a polysiliconfilm) using ozone water. A resist mask is then formed and the siliconfilm is etched to form island-like semiconductor layers separated fromone another and having desired shapes. After the semiconductor layersare formed the resist mask is removed.

The oxide film is removed by an etchant containing fluoric acid, and atthe same time, the surface of the silicon film is washed. Then, aninsulating film mainly containing silicon is formed to serve as a gateinsulating film 803. The gate insulating film here is a siliconoxynitride film (composition ratio: Si=32%, O=59%, N=7%, H=2%) formed byplasma CVD to have a thickness of 115 nm.

Next, a laminate of a first conductive film with a thickness of 20 to100 nm and a second conductive film with a thickness of 100 to 400 nm isformed on the gate insulating film. In this example, a tantalum nitridefilm with a thickness of 50 nm is formed on the gate insulating film 803and then a tungsten film with a thickness of 370 nm is laid thereon. Theconductive films are patterned by the procedure shown below to form gateelectrodes and wires.

The conductive materials of the first conductive film and secondconductive film are elements selected from the group consisting of Ta,W, Ti, Mo, Al, and Cu, or alloys or compounds mainly containing theabove elements. The first conductive film and the second conductive filmmay be semiconductor films, typically polycrystalline silicon films,doped with phosphorus or other impurity elements or may be Ag—Pd—Cualloy films. The present invention is not limited to a two-layerstructure conductive film. For example, a three-layer structureconsisting of a 50 nm thick tungsten film, 500 nm thick aluminum-siliconalloy (Al—Si) film, and 30 nm thick titanium nitride film layered inthis order may be employed. When the three-layer structure is employed,tungsten of the first conductive film may be replaced by tungstennitride, the aluminum-silicon alloy (Al—Si) film of the secondconductive film may be replaced by an aluminum-titanium alloy (Al—Ti)film, and the titanium nitride film of the third conductive film may bereplaced by a titanium film. Alternatively, a single-layer conductivefilm may be used.

ICP (inductively coupled plasma) etching is preferred for etching of thefirst conductive film and second conductive film (first etchingtreatment and second etching treatment). By using ICP etching andadjusting etching conditions (the amount of electric power applied to acoiled electrode, the amount of electric power applied to a substrateside electrode, the temperature of the substrate side electrode, and thelike), the films can be etched and tapered as desired. The first etchingtreatment is conducted after a resist mask is formed. The first etchingconditions include applying an RF (13.56 MHz) power of 700 W to a coiledelectrode at a pressure of 1 Pa, employing CF₄, Cl₂, and O₂ as etchinggas, and setting the gas flow rate ratio thereof to 25:25:10 (sccm). Thesubstrate side (sample stage) also receives an RF power of 150 W (13.56MHz) to apply a substantially negative self-bias voltage. The area(size) of the substrate side electrode is 12.5 cm×12.5 cm and the coiledelectrode is a disc 25 cm in diameter (here, a quartz disc on which thecoil is provided). The W film is etched under these first etchingconditions to taper it around the edges. Thereafter, the first etchingconditions are switched to the second etching conditions withoutremoving the resist mask. The second etching conditions include usingCF₄ and Cl₂ as etching gas, setting the gas flow rate ratio thereof to30:30 (sccm), and giving an RF (13.56 MHz) power of 500 W to a coiledelectrode at a pressure of 1 Pa to generate plasma for etching for about30 seconds. The substrate side (sample stage) also receives an RF powerof 20 W (13.56 MHz) to apply a substantially negative self-bias voltage.Under the second etching conditions where a mixture of CF₄ and Cl₂ isused, the W film and the TaN film are etched to almost the same degree.The first etching conditions and the second etching conditionsconstitute the first etching treatment.

Next follows the second etching treatment with the resist mask kept inplace. The third etching conditions include using CF₄ and Cl₂ as etchinggas, setting the gas flow rate ratio thereof to 30:30 (sccm), and givingan RF (13.56 MHz) power of 500 W to a coiled electrode at a pressure of1 Pa to generate plasma for etching for 60 seconds. The substrate side(sample stage) also receives an RF power of 20 W (13.56 MHz) to apply asubstantially negative self-bias voltage. Then, the third etchingconditions are switched to the fourth etching conditions withoutremoving the resist mask. The fourth etching conditions include usingCF₄, Cl₂, and O₂ as etching gas, setting the gas flow rate ratio thereofto 20:20:20 (sccm), and giving an RF (13.56 MHz) power of 500 W to acoiled electrode at a pressure of 1 Pa to generate plasma for etchingfor about 20 seconds. The substrate side (sample stage) also receives anRF power of 20 W (13.56 MHz) to apply a substantially negative self-biasvoltage. The third etching conditions and the fourth etching conditionsconstitute the second etching treatment. At this stage, gate electrode804 and wires 805 to 807 having the first conductive layer 804 a as thelower layer and the second conductive layer 804 b as the upper layer areformed.

Next, the resist mask is removed for the first doping treatment to dopewith the entire surface using the gate electrodes 804 to 807 as masks.The first doping treatment employs ion doping or ion implantation. Here,ion doping conditions are that the dose is set to 1.5×10¹⁴ atoms/cm²,and the acceleration voltage is set from 60 to 100 keV. As an impurityelements that imparts the n-type conductivity, phosphorus (P) or arsenic(As) is typically used. The first impurity region (n⁻⁻ region) 822 to825 are formed in a self-aligning manner.

Masks formed from resist are newly formed. At this moment, since the offcurrent value of the switching TFT is lowered, the masks are formed tooverlap the channel formation region of a semiconductor layer formingthe switching TFT of the pixel portion 901, and a portion thereof. Themasks are formed to protect the channel formation region of thesemiconductor layer forming the p-channel TFT 906 of the driver circuitand the periphery thereof. In addition, the masks are formed to overlapthe channel formation region of the semiconductor layer forming thecurrent control TFT 904 of the pixel portion 901 and the peripherythereof.

An impurity region (n region) that overlaps with a portion of the gateelectrode is formed by conducting selectively the second dopingtreatment using the masks from the resist. The second doping treatmentis employs ion doping or ion implantation. Here, ion doping is used, theflow rate of gas obtained by diluting phosphine (PH₃) with hydrogen to5% is set to 30 sccm, the dose is set to 1.5×10¹⁴ atoms/cm², and theacceleration voltage is set to 90 keV. In this case the masks made fromresist and the second conductive layer serve as masks against theimpurity element that imparts the n-type conductivity and secondimpurity regions 311 and 312 are formed. The second impurity regions aredoped with the impurity element that imparts the n-type conductivity ina concentration range of 1×10¹⁶ to 1×10¹⁷ atoms/cm³. Here, the sameconcentration range as the second impurity region is referred to as a n⁻region.

Third doping treatment is conducted without removing the resist masks.The third doping treatment is employs ion doping or ion implantation. Asimpurity elements imparts n-type conductivity, phosphorus (P) or arsenic(As) are used typically. Here, ion doping is used, the flow rate of gasobtained by diluting phosphine (PH₃) with hydrogen to 5% is set to 40sccm, the dose is set to 2×10¹⁵ atoms/cm², and the acceleration voltageis set to 80 keV. In this case the masks made from resist and the secondconductive layer serve as masks against the impurity element thatimparts the n-type conductivity and third impurity regions 813, 814, 826to 828 are formed. The third impurity regions are doped with theimpurity element that imparts the n-type conductivity in a concentrationrange of 1×10²⁰ to 1×10²¹ atoms/cm³. Here, the same concentration rangeas the third impurity region is referred to as a n⁺ region.

After removing the resist mask and the new resist mask is formed, thefourth doping treatment is conducted. The fourth impurity regions 818,819, 832, 833 and the fifth impurity regions 816, 817, 830, 831 areformed in which impurity elements imparts p-type conductivity are addedto the semiconductor layer forming the p-channel TFT by the fourthdoping treatment.

The concentration of the impurity element that imparts the p-typeconductivity is set from 1×10²⁰ to 1×10²¹ atoms/cm³ to add to the fourthimpurity regions 818, 819, 832, and 833. The fourth impurity regions818, 819, 832, and 833 being region (n⁻⁻ region) are already doped withphosphorus (P) in the previous step but are doped with the impurityelement that imparts the p-type conductivity in a concentration 1.5 to 3times the phosphorus concentration to obtain the p-type conductivity.Here, a region having the same concentration range as the fourthimpurity regions is also called a p⁺ region.

The fifth impurity regions 816, 817, 830, and 831 are formed in theregion overlaps with the taper portion of the second conductive layer.The impurity elements imparts p-type conductivity is added thereto atthe concentration range from 1×10¹⁸ to 1×10²⁰ atoms/cm³. Here, theregion having the same concentration range as the fifth impurity regionsis referred to as p⁻ region.

Through the above steps, an impurity region having the n-type or p-typeconductivity is formed in each semiconductor layer. The conductivelayers 804 to 807 become the gate electrode of TFT.

An insulating is formed to cover almost the entire surface (not shown).In this example, the silicon oxide film having 50 nm in thickness isformed by plasma CVD method. Of course, the insulating film is notlimited to a silicon oxide film and a single layer or laminate of otherinsulating films containing silicon may be used.

The next step is activation treatment of the impurity elements used todope the semiconductor layers. The activation step employs rapid thermalannealing (RTA) using a lamp light source, irradiation of a laser, heattreatment using a furnace, or a combination of these methods.

In the example shown in this example, the interlayer insulating film isformed after the above-described activation. However, the insulatingfilm may be formed before the activation.

The first interlayer insulating film 808 made from a silicon nitridefilm is formed. Then, the semiconductor layers are subjected to heattreatment (at 300 to 550° C. for 1 to 12 hours) to hydrogenate thesemiconductor layers. This step is for terminating dangling bonds in thesemiconductor layers using hydrogen contained in the first interlayerinsulating film 808. The semiconductor layers are hydrogenatedirrespective of the presence of the interlayer insulating film that is asilicon oxide film. Other hydrogenation methods employable includeplasma hydrogenation (using hydrogen excited by plasma).

Next, a second interlayer insulating film 809 is formed on the firstinterlayer insulating film 808 from an organic insulating material. Inthis example, an acrylic resin film 809 a is formed to have a thicknessof 1.6 μm, and a silicon nitride film 809 b is formed to have athickness of 200 nm by sputtering.

The pixel electrode 834 in contact with the drain region of the currentcontrol TFT 904 formed from the p-channel TFT 904 is formed to overlapin contact with the connecting electrode that is formed later. In thisexample, the pixel electrode functions as an anode of OLED, and is atransparent conductive film for the light emitted from OLED radiatingthrough the pixel electrode.

Formed next are contact holes reaching the conductive layers that serveas the gate electrodes or gate wires and contact holes reaching theimpurity regions. In this example, etching treatment is conductedseveral times in succession. Also, in this example, the secondinterlayer insulating film is used as an etching stopper to etch thethird interlayer insulating film, then the first interlayer insulatingfilm is used as an etching stopper to etch the second interlayerinsulating film, and then the first interlayer insulating film isetched.

Thereafter, electrodes 835 to 841, specifically, a source wire, a powersupply line, a lead-out electrode, a connection electrode, etc. areformed from Al, Ti, Mo, or W. Here, the electrodes and wires areobtained by patterning a laminate of a Ti film (100 nm in thickness), anAl film containing silicon (350 nm in thickness), and another Ti film(50 nm in thickness). The source electrode, source wire, connectionelectrode, lead-out electrode, power supply line, and the like are thusformed as needed. A lead-out electrode for the contact with a gate wirecovered with an interlayer insulating film is provided at an end of thegate wire, and other wires also have at their ends input/output terminalportions having a plurality of electrodes for connecting to externalcircuits and external power supplies. The connection electrode 841provided as to contact and overlap with the pixel electrode 834 that ispreviously formed is in contact with the drain region of the currentcontrol TFT 904.

A driving circuit 902 having a CMOS circuit in which an n-channel TFT905 and a p-channel TFT 906 are combined complementarily and a pixelportion 901 with a plurality of pixels each having an n-channel TFT 903or a p-channel TFT 904 are formed in the manner described above.

Next, insulators 842 a and 843 b referred to as a bank are formed oneach end of the pixel electrode 834 so as to cover each end of the pixelelectrode 834. The banks 842 a and 843 b are formed from an insulatingfilm containing silicon or a resin film. In this example, the bank 842 ais formed by patterning the insulating film made from the organic resinfilm, the silicon nitride film is formed by sputtering, and the bank 842b is formed by patterning.

Next, an EL layer 843 and the cathode 844 of OLED are formed on thepixel electrode 834 whose ends are covered by the banks. In thisexample, the EL layer 843 and the cathode 844 of OLED are evaporated bythe deposition apparatus shown in Embodiment 1. An evaporation method isaccording to Embodiment 1 or Example 1. High-density and high purity ELlayer may be formed by conducting evaporation in vacuum while heatingthe substrate.

An EL layer 843 (a layer for light emission and for moving of carriersto cause light emission) has a light emitting layer and a freecombination of electric charge transporting layers and electric chargeinjection layers. For example, a low molecular weight organic ELmaterial or a high molecular weight organic EL material is used to forman EL layer. An EL layer may be a thin film formed of a light emittingmaterial that emits light by singlet excitation (fluorescence) (asinglet compound) or a thin film formed of a light emitting materialthat emits light by triplet excitation (phosphorescence) (a tripletcompound). Inorganic materials such as silicon carbide may be used forthe electric charge transporting layers and electric charge injectionlayers. Known organic EL materials and inorganic materials can beemployed.

It is said that the preferred material of a cathode 844 is a metalhaving a small work function (typically, a metal element belonging toGroup 1 or 2 in the periodic table) or an alloy of such metal. The lightemission efficiency is improved as the work function becomes smaller.Therefore, an alloy material containing Li (lithium) that is one ofalkali metals is particularly desirable as the cathode material. Thecathode also functions as a wire common to all pixels and has a terminalelectrode in an input terminal portion through a connection wire.

The stage completed so far steps is shown in FIG. 8. Though theswitching TFT 903 and the current supply TFT for OLED (the currentcontrol TFT) are shown in FIG. 8, it goes without saying that it is notlimited thereof, various circuits formed from plural TFTs may beprovided at the end of the gate electrode of TFT.

Next, the OLED having at least a cathode, an organic compound layer, andan anode is preferably sealed by an organic resin, a protective film, asealing substrate, or a sealing can to cut the OLED completely off fromthe outside and prevent permeation of external substances, such asmoisture and oxygen, that accelerate degradation due to oxidization ofthe EL layer. However, it is not necessary to provide the protectivefilm or the like in the input/output terminal portions to which an FPCneeds to be connected later.

The FPC (flexible printed circuit) is attached to the electrodes of theinput/output terminal portions using an anisotropic conductive material.The anisotropic conductive material is composed of a resin andconductive particles several tens to several hundreds μm in diameterwhose surfaces are plated by Au or the like. The conductive particleselectrically connect the electrodes of the input/output terminalportions with wires formed in the FPC.

If necessary, an optical film such as a circularly polarizing platecomposed of a polarizing plate and a phase difference plate may beprovided and an IC chip may be mounted.

Through the above steps, a module type light emitting device to which anFPC is connected is completed.

This example may be freely combined with Embodiments 1, 2, and Examples1 to 4.

Example 6

The top surface view and the cross-sectional view of the module typelight emitting device (also referred to as EL module) obtained byExample 5 are shown.

FIG. 9A is a view of a top surface view of EL module and FIG. 9B is across-sectional view taken along the line of A-A′ of FIG. 9A. FIG. 9Ashows that the base insulating film 401 is formed on the bonding member400 (for example, the second bonding member and the like), and the pixelportion 402, the source side driver circuit 404, and the gate sidedriver circuit 403 are formed thereon. These pixel portion and drivercircuit may be obtained according to above-mentioned Example 5.

The reference numeral 418 is an organic resin and 419 is a protectivefilm. The pixel portion and the driver circuit portion are covered bythe organic resin 418, and the organic resin 418 is covered by theprotective film 419. In addition, the organic resin may be sealed by thecover material using the bonding member. The cover material can beadhered as a support medium before peeling-off is subjected. Inaddition, reference numeral 408 represents a wiring for transmittingsignals to be inputted into the source side driving circuit 404 and thegate side driving circuit 403, and it receives a video signal and aclock signal from the FPC (flexible print circuit) 409 which becomes anexternal input terminal. In addition, here, only FPC is shown in thefigure, but a printed wiring board (PWB) may be attached to this FPC. Alight emitting device in the present specification is assumed to containnot only a light emitting device itself but also a state in which FPC orPWB is attached thereto.

The cross-sectional structure shown in FIG. 9B is described. A baseinsulating film 401 is formed on the bonding member 400. The pixelportion 402 and the gate driving circuit 403 are formed in contact withthe insulating film 401. The pixel portion 402 is composed of thecurrent control TFT 411 and plural pixels including the pixel electrode412 that is connected electrically to the drain of the current controlTFT 411. In addition, the gate driving circuit 403 is formed by using aCMOS circuit that is combined with the n-channel TFT 413 and thep-channel TFT 414.

The TFTs (including 411, 413, and 414) may be manufactured according ton-channel TFT of Example 5 and p-channel TFT of Example 5. Though onlythe current supply TFT for OLED (the current control TFT 411) is shownin FIG. 9, it goes without saying that it is not limited thereof,various circuits formed from plural TFTs may be provided at the end ofthe gate electrode of TFT.

The pixel portion 402, the source side driver circuit 404, and the gateside driver circuit 403 are formed on the same substrate according toExample 5.

The pixel electrode 412 functions as a cathode of the light emittingelement (OLED). The bank 415 is formed at the both ends portion of thepixel electrode 412. The organic compound layer 416 and the anode 417 ofthe light emitting element are formed on the pixel electrode 412.

As the organic compound layer 416, it should be appreciated that theorganic compound layer (a layer for carrying out light emission andmovement of carriers therefore) may be formed by freely combining alight emitting layer, an electric charge transport layer or an electriccharge injection layer.

The anode 417 functions as a common wiring to all pixels, and iselectrically connected to an FPC 409 through a connection wiring 408.Further, elements which are contained in the pixel portion 402 and thegate side driving circuit 403 are all covered by the anode 417, anorganic resin 418 and a protective film 419.

In addition, as the organic resin 418, it is preferable to use atransparent or half transparent material to visible light to the extentpossible. Further, it is preferable that the organic resin 418 is amaterial which does not transmit impurities such as moisture and oxygento the extent possible.

Also, it is preferred that after the light emitting element has beencompletely covered with the organic resin 418, the protective film 419be at least formed on the surface (exposed surface) of the organic resin418 as shown in FIGS. 7A and 7B. The protective film may be formed onthe entire surface including the back surface of the substrate. In sucha case, it is necessary to carefully form the protective film so that noprotective film portion is formed at the position where the externalinput terminal (FPC) is provided. A mask may be used to prevent filmforming of the protective film at this position. The external inputterminal portion may be covered with a tape such as a tape made ofTeflon (registered trademark) used as a masking tape in a CVD apparatusto prevent film forming of the protective film. The silicon nitridefilm, the DLC film, or AlNxOy film may be used as the protective film419.

The light emitting element constructed as described above is enclosedwith the protective film 419 to completely isolate the light emittingelement from the outside, thus preventing materials such as water andoxygen which accelerate degradation of the organic compound layer byoxidation from entering from the outside. Thus, the light emittingdevice having improved reliability is obtained. The steps from thedeposition to the sealing of EL layer may be conducted by using theapparatus shown in FIGS. 5 to 7.

Another arrangement is conceivable in which a pixel electrode is used asan anode and an organic compound layer and a cathode are made inlamination to emit light in a direction opposite to the directionindicated in FIG. 9. FIG. 10 shows an example of such an arrangement.The top view thereof is the same as the top view shown in FIG. 9 andwill therefore be omitted.

The structure shown in the cross-sectional view of FIG. 7 will bedescribed. An insulating film 610 is formed on a substrate 600, and apixel portion 602 and a gate-side drive circuit 603 are formed above theinsulating film 610. The pixel portion 602 is formed by a plurality ofpixels including a current control TFT 611 and a pixel electrode 612electrically connected to the drain of the current control TFT 611. Agate side driver circuit 603 is formed by using a CMOS circuit having acombination of an n-channel TET 613 and a p-channel TFT 614.

These TFTs (611, 613, 614, etc.) may be fabricated in the same manner asthe n-channel TFT of Example 5 and the p-channel TFT of Example 5.Though only the current supply TFT for OLED (the current control TFT411) is shown in FIG. 10, it goes without saying that it is not limitedthereof, various circuits formed from plural TFTs may be provided at theend of the gate electrode of TFT.

The pixel electrode 612 functions as an anode of the light emittingelement (OLED). Banks 615 are formed at opposite ends of the pixelelectrode 612, and an organic compound layer 616 and an anode 617 of thelight emitting element are formed over the pixel electrode 612.

The anode 617 also functions as a common wiring element connected to allthe pixels and is electrically connected to a FPC 609 via connectionwiring 608. All the elements included in the pixel portion 602 and thegate-side drive circuit 603 are covered with the anode 617, an organicresin 618 and a protective film 619. A cover member 620 is bonded to theelement layer by an adhesive. A recess is formed in the cover member anda desiccant 621 is set therein.

In the arrangement shown in FIG. 10, the pixel electrode is used as thecathode while the organic compound layer and the anode are formed inlamination, so that light is emitted in the direction of the arrow inFIG. 10.

While the top gate TFTs have been described by way of example, thepresent invention can be applied irrespective of the TFT structure. Forexample, the present invention can be applied to bottom gate (inverselystaggered structure) TFTs and staggered structure TFTs.

This example may be freely combined with Embodiments 1, 2, and Examples1 to 5.

Example 7

By implementing the present invention, EL modules (active matrix liquidcrystal module, active matrix EL module and active matrix EC module) canbe completed. Namely, by implementing the present invention, all of theelectronic equipments into which the various modules are built arecompleted. Following can be given as such electronic equipments: videocameras; digital cameras; head mounted displays (goggle type displays);car navigation systems; car stereos; personal computers; portableinformation terminals (mobile computers, mobile phones or electronicbooks etc.) etc. Examples of these are shown in FIGS. 11 and 12. FIG.11A is a personal computer which comprises: a main body 2001; an imageinput section 2002; a display section 2003; and a keyboard 2004 etc.

FIG. 11B is a video camera which comprises: a main body 2101; a displaysection 2102; a voice input section 2103; operation switches 2104; abattery 2105 and an image receiving section 2106 etc.

FIG. 11C is a mobile computer which comprises: a main body 2201; acamera section 2202; an image receiving section 2203; operation switches2204 and a display section 2205 etc. FIG. 11D is a goggle type displaywhich comprises: a main body 2301; a display section 2302; and an armsection 2303 etc. FIG. 11E is a player using a recording medium in whicha program is recorded (hereinafter referred to as a recording medium)which comprises: a main body 2401; a display section 2402; a speakersection 2403; a recording medium 2404; and operation switches 2405 etc.This apparatus uses DVD (digital versatile disc), CD, etc. for therecording medium, and can perform music appreciation, film appreciation,games and use for Internet. FIG. 11F is a digital camera whichcomprises: a main body 2501; a display section 2502; a view finder 2503;operation switches 2504; and an image receiving section (not shown inthe figure) etc.

FIG. 12A is a mobile phone which comprises: a main body 2901; a voiceoutput section 2902; a voice input section 2903; a display portion 2904;operation switches 2905; an antenna 2906; and an image input section(CCD, image sensor, etc.) 2907 etc.

FIG. 12B is a portable book (electronic book) which comprises: a mainbody 3001; display portions 3002 and 3003; a recording medium 3004;operation switches 3005 and an antenna 3006 etc.

FIG. 12C is a display which comprises: a main body 3101; a supportingsection 3102; and a display portion 3103 etc. In addition, the displayshown in FIG. 12C has small and medium-sized or large-sized screen, forexample a size of 5 to 20 inches. Further, to manufacture the displaypart with such sizes, it is preferable to mass-produce by gang printingby using a substrate with one meter on a side.

As described above, the applicable range of the present invention isextremely large, and the invention can be applied to electronicequipments of various areas. Note that the electronic devices of thisexample can be achieved by utilizing any combination of constitutions inEmbodiments 1 to 3, and Examples 1 to 6.

Example 8

In the present example, a novel film formation method is described.

As a typical example of a physical film formation method, a vacuumevaporation which forms a film by evaporating an evaporating materialfrom an evaporation source under vacuum is known. Further, as a typicalexample of chemical film formation method, CVD (chemical vapordeposition) which forms a film by chemical reaction on a substratesurface or in a vapor is known.

The present example provides a novel film formation method. That is,when an organic compound material is evaporated from an evaporationsource in a film formation chamber, a minute amount of a material gaswhich comprises, as an ingredient, a material which is smaller than aparticle of the organic compound material is made flow to include thesmall atomic radius material in an organic compound film.

As the small atomic radius material gas, one kind or a plural kindsselected from a silane group gas (monosilane, disilane and trisilane),SiF₄, GeH₄, GeF₄, SnH₄ and hydrocarbon group gas (CH₄, C₂H₂, C₂H₄ andC₆H₆) can be used. Before the gas is introduced inside the apparatus,the gas is highly purified by a gas purifying machine. Accordingly, itis necessary to provide the gas purifying machine so that after the gasis highly purified, the gas is introduced into the evaporationapparatus. Thereby, oxygen, water and other impurities contained in agas can be previously removed. Therefore, it is possible to preventthese impurities from being introduced inside the apparatus.

For example, when a monosilane gas is introduced at several sccm intothe film formation chamber in which an organic material is deposited byevaporation, SiH₄ floating inside the film formation chamber enters intoa thin film which is formed over a substrate by depositing an organicmaterial evaporated from the evaporation source. Then, a small atomicradius SiH₄ as it is or SiH_(x) is buried between relatively largeparticle radius organic material molecules to be contained in the film.During evaporation, the evaporation source is heated at about 100° C.Because monosilane has a decomposition temperature of about 550° C., itdoes not decompose. Depending on an organic material to be evaporated,it reacts with SiH₄ or SiH_(x) to form a compound. Further, becauseoxygen (or moisture) slightly remaining in the film formation chamber iscaptured to form SiO_(x), oxygen (or moisture) which is a factordeteriorating an organic material can be reduced in the film formationchamber and in the film. As a result, it is possible to improvereliability of a light emitting element.

When there is a spacing between the organic material molecules in thefilm, oxygen easily enters the spacing to cause deterioration. Becausethis spacing should be buried, reliability of the light emitting elementcan be improved by using SiF₄, GeH₄, GeF₄, SnH₄ and hydrocarbon groupgas (CH₄, C₂H₂, C₂H₄ and C₆H₆).

As the above organic material, α-NPD(4,4′-bis-[N-(naphthyl)-N-phenyl-amino]biphenyl), BCP (basocuproine),MTDATA (4,4′,4″-tris(N-3-methylphenyl-N-phenyl-amino) triphenylamine),Alq₃ (tris-8-quinolinorathoaluminum derivative) can be enumerated.

The present example is effective when forming a mixed region shown inFIG. 4 by coevaporation, or when depositing a functional region (havingan electron transporting function). As a result, reliability of a lightemitting element is improved.

A vacuum degree of the film formation chamber is 10⁻⁸ to 10⁻¹ Torr,preferably 10⁻⁷ to 10⁻² Torr. A dry pump, a cryopump, or a turbomolecular pump of magnetic float type is provided for a vacuumevaporation treatment chamber connected with the film formation chamber.Further, when a surface of a material of an inner wall of the filmformation chamber is made small, adsorption of impurities such as oxygenand water can be made small. Therefore, stainless steel (SUS) oraluminum mirrored by electrolytic polishing is used. Thereby, it ispossible to maintain a vacuum degree of 10⁻⁸ to 10⁻¹ Torr inside thefilm formation chamber. Further, a material such as ceramics treated toreduce a pore to extremely small number is used for an inner member. Itis to be noted that it is preferred that these have surface flatnesshaving a center line average flatness of 3 nm or less.

A constitution of a film formation apparatus in the present inventionwill be explained using FIG. 15. FIG. 15 shows an example showing across sectional view of the film formation apparatus in the presentinvention.

In FIG. 15, an evaporation mask 1502 a fixed in contact with a substrate1501 by a holder is provided. Further, under it, evaporation sourceholders 1506 being capable of being heated at different temperaturesrespectively are provided. It is to be noted that these evaporationsources are provided opposed to the substrate.

A material chamber 1508 is a space of the evaporation holders 1506comprising a conductive metal material. When an organic compound 1507provided inside is heated to a sublimation temperature by a heatingmeans (typically a resistance heating method) provided for theevaporation holders, it is deposited over a surface of the substratethrough vaporization. It is to be noted that when conducting theevaporation, an electrode 1502 b is moved to a position where it doesnot prevent the evaporation. Further, the organic compound 1507 isprovided in respective containers (typically crucible and evaporationboat).

Further, during the evaporation, a material gas is introduced at severalsccm to contain the material gas in the film. The material gas or mainingredient of the material gas is contained in the film at 0.01 atoms %to 5 atoms %, preferably 0.1 atoms % to 2 atoms %. As a gas introducedinto the film formation chamber 1503, one kind or a plural kindsselected from a silane group gas (monosilane, disilane and trisilane),SiF₄, GeH₄, GeF₄, SnH₄ and hydrocarbon group gas (CH₄, C₂H₂, C₂H₄ andC₆H₆) can be used.

The film containing an organic compound formed using FIG. 15 containsthe material gas or the main ingredient of the material gas, and oxygenand moisture are hard to enter the film. Therefore, a light emittingelement using this film containing the organic compound is improved inreliability.

Further, when conducting coevaporation by evaporating a plurality ofdifferent materials, two kinds of organic compounds are simultaneouslyevaporated and the above material gas is introduced to form a mixedregion containing the two kinds of organic compounds and the materialgas or the main ingredient of the material gas.

Further, after evaporating the first organic compound, the secondorganic compound is evaporated under the same evaporation atmosphere andthe above material gas is introduced to form a mixed region between thefirst functional region and the second functional region. In the presentexample, the first organic compound is vaporized by previous resistanceheating and the first shutter 1509 is opened during the evaporation.Thereby, it is dispersed toward the substrate. In this way, the firstfunctional region shown in FIG. 4A can be formed. Next, the secondshutter 1519 is opened for the evaporation to form a mixed region.

Further, in forming the mixed region, the mixed region may haveconcentration gradient. Further, the present invention is applicablewhen a material capable of converting a triplet excitation energy into alight emission is added to the mixed region as a dopant. Further, whenconducting coevaporation, it is preferred that directions of evaporatingorganic compounds are crossed at a position of an object to beevaporated so that the organic compounds are mixed with each other.

Further, an adhesion prevention shield 1505 is provided to prevent anorganic compound from adhering to an inner wall of the film formationchamber during the evaporation.

Further, because the evaporation holder 1506 provided with heating meanssuch as a heater is raised to a high temperature, it is preferred thatit is covered with a heat insulating material 1504.

Further, plasma may be generated provided that it does not impart damageto the film containing organic compound. It is possible to generateplasma between the evaporation mask 1502 a connected with a highfrequency power source 1500 a through a capacitor 1500 b and anelectrode 1502 b.

Further, phosphine gas may be introduced in addition to monosilane.Further, instead of monosilane, AsH₃, B₂H₂, BF₄, H₂Te, Cd(CH₃)₂,Zn(CH₃)₂, (CH₃)₃In, H₂Se, BeH₂, trimethyl gallium or triethyl galliumcan be used.

The present example can be freely combined with either one ofEmbodiments 1 to 3 and Examples 1 to 7.

According to the invention, while a substrate being heated in vacuum,deposition is carried out and film with a desired thickness is formed,so that an organic compound layer with a high density and a high puritycan be formed.

Further, according to the invention, while a substrate being heated invacuum, deposition is carried out a plurality of times, so thatmolecules between respectively neighboring layers are fitted better.Especially, in the case of forming mixed regions, the molecules in themixed regions are fitted better. Consequently, the driving voltage canbe decreased further and the brightness deterioration can be suppressed.

Further, according to the invention, in a single film formation chamber,it is made possible to carry out annealing in vacuum before filmformation, annealing in vacuum during film formation, and annealing invacuum after film formation to result in improvement of the throughput.

Further, according to the invention, deposition materials adhering tojigs installed in the inside of the film formation apparatus and innerwall of the film formation apparatus can be removed without exposingthem to the atmospheric air.

What is claimed is:
 1. A film formation apparatus for forming a filmover a substrate by depositing an organic compound material from adeposition source provided opposite to the substrate, said filmformation apparatus comprising: a film formation chamber to provide saidsubstrate therein; a deposition source provided in said film formationchamber; a means provided in said film formation chamber for heating thedeposition source; a heating means provided in said film formationchamber for heating a mask; and a vacuum gas discharge treatment chamberfor vacuum evacuating the film formation chamber, wherein the filmformation chamber is connected with the vacuum gas discharge treatmentchamber.
 2. An apparatus according to claim 1, wherein said filmformation chamber is kept in vacuum degree of 1×10⁻³ Torr or lowerpressure.
 3. An apparatus according to claim 1 wherein a plurality ofdeposition sources are provided and contain organic compoundsrespectively having different functions and at least two types of theorganic compounds are simultaneously deposited.
 4. An apparatusaccording to claim 1 wherein the temperature T₁ of said substrate iscontrolled to be lower than the temperature T₃ of said depositionsource.
 5. An apparatus according to claim 1 wherein the temperature T₁of said substrate is controlled to be in a range from 50° C. to 200° C.6. A film formation apparatus for forming a film over a substrate bydepositing an organic compound material from a deposition sourceprovided opposite to the substrate, said film formation apparatuscomprising; a film formation chamber to provide said substrate therein,an adhesion prevention means provided in said film formation chamber forpreventing film formation in the inner wall; a heating means provided insaid film formation chamber for heating the adhesion prevention means;the deposition source provided in said film formation chamber, a meansprovided in said film formation chamber for heating the depositionsource; and a heating means provided in said film formation chamber forheating a mask; and a vacuum gas discharge treatment chamber for vacuumevacuating the film formation chamber, wherein the film formationchamber is connected with said vacuum gas discharge treatment chamber.7. An apparatus according to claim 6, wherein said film formationchamber is kept in vacuum degree of 1×10⁻³ Torr or lower pressure.
 8. Anapparatus according to claim 6 wherein a plurality of deposition sourcesare provided and contain organic compounds respectively having differentfunctions and at least two types of the organic compounds aresimultaneously deposited.
 9. An apparatus according to claim 6 whereinthe temperature T₁ of said substrate is controlled to be lower than thetemperature T₃ of said deposition source.
 10. An apparatus according toclaim 6 wherein the temperature T₁ of said substrate is controlled to bein a range from 50° C. to 200° C.
 11. An apparatus according to claim 6wherein the temperature T₁ of said substrate is controlled to be lowerthan the temperature T₂ of said adhesion prevention means by at least10° C. and the temperature T₂ of said adhesion prevention means iscontrolled to be lower than the temperature T₃ of said depositionsource.
 12. A film formation apparatus comprising: a load chamber, atransportation chamber, and a film formation chamber joined to eachother in series, wherein said film formation chamber has a function ofconforming the positioning of a mask and a substrate and said filmformation chamber is connected with a vacuum gas discharge treatmentchamber for vacuum evacuating the film formation chamber and comprisesan adhesion prevention means for preventing film formation in the innerwall, a heating means for heating the adhesion prevention means, thedeposition source, a means for heating the deposition source, and aheating means for heating a mask.
 13. An apparatus according to claim12, wherein said film formation chamber is kept in vacuum degree of1×10⁻³ Torr or lower pressure.
 14. An apparatus according to claim 12wherein a plurality of deposition sources are provided and containorganic compounds respectively having different functions and at leasttwo types of the organic compounds are simultaneously deposited.
 15. Anapparatus according to claim 12 wherein the temperature T₁ of saidsubstrate is controlled to be lower than the temperature T₃ of saiddeposition source.
 16. An apparatus according to claim 12 wherein thetemperature T₁ of said substrate is controlled to be in a range from 50°C. to 200° C.
 17. An apparatus according to claim 12 wherein thetemperature T₁ of said substrate is controlled to be lower than thetemperature T₂ of said adhesion prevention means by at least 10° C. andthe temperature T₂ of said adhesion prevention means is controlled to belower than the temperature T₃ of said deposition source.
 18. A filmformation apparatus comprising: a load chamber; a transportation chamberconnected with said load chamber; and a film formation chamber connectedwith said transportation chamber, wherein said transportation chamberhas a function of conforming the positioning of a mask and a substrateand said film formation chamber is connected with a vacuum gas dischargetreatment chamber for vacuum evacuating the film formation chamber andsaid film formation chamber comprises an adhesion prevention means forpreventing film formation in the inner wall, a heating means for heatingthe adhesion prevention means, the deposition source, a means forheating the deposition source, and a heating means for heating a mask.19. An apparatus according to claim 18, wherein said film formationchamber is kept in vacuum degree of 1×10⁻³ Torr or lower pressure. 20.An apparatus according to claim 18 wherein a plurality of depositionsources are provided and contain organic compounds respectively havingdifferent functions and at least two types of the organic compounds aresimultaneously deposited.
 21. An apparatus according to claim 18 whereinthe temperature T₁ of said substrate is controlled to be lower than thetemperature T₃ of said deposition source.
 22. An apparatus according toclaim 18 wherein the temperature T₁ of said substrate is controlled tobe in a range from 50° C. to 200° C.
 23. An apparatus according to claim18 wherein the temperature T₁ of said substrate is controlled to belower than the temperature T₂ of said adhesion prevention means by atleast 10° C. and the temperature T₂ of said adhesion prevention means iscontrolled to be lower than the temperature T₃ of said depositionsource.
 24. A film formation apparatus for forming a film over asubstrate by depositing an organic compound material from a depositionsource provided opposite to the substrate, said film formation apparatuscomprising: a film formation chamber to provide said substrate therein,a deposition source provided in said film formation chamber; a meansprovided in said film formation chamber for heating the depositionsource; a heating means provided in said film formation chamber forheating a substrate; a mask provided in said film formation chamber, andan electrode provided in said film formation chamber and opposite to themask; and a vacuum gas discharge treatment chamber for vacuum evacuatingthe film formation chamber, wherein the film formation chamber isconnected with the vacuum gas discharge treatment chamber and plasma isgenerated in the film formation chamber.
 25. An apparatus according toclaim 10; wherein said mask is made of a conductive material and eitherone of said mask and said electrode is connected with a high frequencypower source.
 26. A film formation apparatus for forming a film over asubstrate by depositing an organic compound material from a depositionsource provided opposite to the substrate, said film formation apparatuscomprising: a film formation chamber to provide said substrate therein;a deposition source provided in said film formation chamber; a meansprovided in said film formation chamber for heating the depositionsource; a heating means provided in said film formation chamber forheating a substrate; and a vacuum gas discharge treatment chamber forvacuum evacuating the film formation chamber, wherein the film formationchamber is connected with the vacuum gas discharge treatment chamber andalso with a cleaning preparatory chamber for radiating laser beam to theinner wall of said treatment chamber.
 27. An apparatus according toclaim 26; wherein said laser beam is scanned by using a galvano-mirror.